CS4FN Advent – Day 16: candy cane or walking aid: designing for everyone, human computer interaction

Welcome to Day 16 of the CS4FN Christmas Computing Advent Calendar in which we’re posting a blog post every day in December until (and including) Christmas Day.

We’re celebrating the breadth of computing research and also the history of CS4FN, a project which has been distributing free magazines to subscribing UK schools since 2005 (ask your teacher to subscribe for next year’s magazine).

Today’s advent calendar picture is of a candy cane which made me think both of walking aids and of support sticks that alert others that the person using it is blind or visually impaired.

A white candy cane with green and red stripes.

We’ve worked with several people over the years to write about their research into making life easier for people with a variety of disabilities. Issue 19 of our magazine (“Touch it, feel it, hear it!”) focused on the DePiC project (‘Design Patterns for Inclusive Collaboration’) which included work on helping visually impaired sound engineers to use recording studio equipment, and you can read one of the articles (see ‘2. The Haptic Wave’) from that magazine below.

Our most recent CS4FN magazine (issue 27, called “Smart Health: decisions, decisions, decisions“) was about Bayesian mathematics and its use in computing, but one of those uses might be an app with the potential to help people with arthritis get medical support when they most need it (rather than having to wait until their next appointment) – download the magazine by clicking on its title and scroll to page 16 & 17 (p9 of the 11 page PDF). Our writing also supports the (obvious) case, that disabled people must be involved at the design and decision-making stages.

 

1. Design for All (and by All!)

by Paul Curzon, QMUL. This article was originally published on the CS4FN website.

Making things work for everyone

Designing for the disabled – that must be a niche market mustn’t it? Actually no. One in five people have a disability of some kind! More surprising still, the disabled have been the inspiration behind some of the biggest companies in the world. Some of the ideas out there might eventually give us all super powers.

Just because people have disabilities doesn’t mean they can’t be the designers, the innovators themselves of course. Some of the most innovative people out there were once labelled ‘disabled’. Just because you are different doesn’t mean you aren’t able!

Where do innovators get their ideas from? Often they come from people driven to support people currently disadvantaged in society. The resulting technologies then not only help those with disabilities but become the everyday objects we all rely on. A classic example is the idea of reducing the kerbs on pavements to make it possible for people in wheelchairs to get around. Turns out of course that they also help people with pushchairs, bikes, roller-blades and more. That’s not just a one-off example, some of the most famous inventors and biggest companies in the world have their roots in ‘design for all’.

Designing for more extreme situations pushes designers into thinking creatively, thinking out of the box. That’s when totally new solutions turn up. Designing for everyone is just a good idea!

2. Blind driver filches funky feely sound machine! The Haptic Wave

by Jane Waite, QMUL. This article was originally published on the CS4FN website.

The blind musician Joey Stuckey in his recent music video commandeers then drives off in a car, and yes he is blind. How can a blind person drive a car, and what has that got to do with him trying to filch a sound machine? So maybe taking the car was just a stunt, but he really did try and run off with a novel sound machine!

As well as fronting his band Joey is an audio engineer. Unlike driving a car, which is all about seeing things around you – signs, cars pedestrians – being an audio engineer seems a natural job for someone who is blind. Its about recording, mixing and editing music, speech and sound effects. What matters most is that the person has a good ear. Having the right skills could easily lead to a job in the music industry, in TV and films, or even in the games industry. It’s also an important job. Getting the sound right is critical to the experience of a film or game. You don’t want to be struggling to hear mumbling actors, or the sound effects to drown out a key piece of information in a game.

Peter Francken in his studio. Image from Wikimedia Commons.

Mixing desks

Once upon a time Audio engineers used massive physical mixing desks. That was largely ok for a blind person as they could remember the positions of the controls as well as feel the buttons. As the digital age has marched on, mixing desks have been replaced by Digital Audio Workstations. They are computer programs and the trouble is that despite being about sound, they are based on vision.

When we learn about sound we are shown pictures of wavy lines: sound waves. Later, we might use an oscilloscope or music editing software, and see how, if we make a louder sound, the curves get taller on the screen: the amplitude. We get to hear the sound and see the sound wave at the same time. That’s this multimodal idea again, two ways of sensing the same thing.

But hang on, sound isn’t really a load of wavy lines curling out of our mouths, and shooting away from guitar strings. Sound is energy and atoms pushing up against each other. But we think of sound as a sound wave to help us understand it. That’s what a computer scientist calls abstraction: representing things in a simpler way. Sound waves are an abstraction, a simplified representation, of sound itself.

Sound waveform image by Gordon Johnson from Pixabay

The representation of sound as sound waves, as a waveform, helps us work with sound, and with Digital Audio Workstations it is now essential for audio engineers. The engineer works with lines, colors, blinks and particularly sound waves on a screen as they listen to the sound. They can see the peaks and troughs of the waves, helping them find the quiet, loud and distinctive moments of a piece of music, at a glance, for example. That’s great as it makes the job much easier…but only if you are fully sighted. It makes things impossible for someone with a visual impairment. You can’t see the sound waves on the editing screen. Touching a screen tells you nothing. Even though it’s ultimately about sounds, doing your job has been made as hard as driving a car. This is rather sad given computers have the potential to make many kinds of work much more accessible to all.

Feel the sound

The DePIC research team, a group of people from Goldsmiths, Queen Mary University of London and Bath Universities with a mission to solve problems that involve the senses, decided to fix it. They’ve created the first ever plug-in software for professional Digital Audio Workstations that makes peak level meters completely accessible. It uses ‘sonification’: it turns those visual signals in to sound! decided to fix the problems. They brought together Computer Scientists, Design experts, and Cognitive Scientists and most importantly of all audio engineers who have visual impairments. Working together over two years in workshops sharing their experiences and ideas, developing, testing and improving prototypes to figure out how a visually impaired engineer might ‘see’ soundwaves. They created the HapticWave, a device that enables a user to feel rather than see a sound wave.

The HapticWave

The HapticWave combines novel hardware and software to provide a new interface to the traditional Digital Audio Workstation. The hardware includes a long wooden box with a plastic slider. As you move the slider right and left you move forward and backwards through the music. On the slider there is a small brass button, called a fader. Tiny embossed stripes on the side of the slider let you know where the fader is relative to the middle and ends of the slider. It moves up and down in sync with the height of the sound wave. So in a quiet moment the fader returns to the centre of the slider. When the music is loud, the fader zooms to the top of the handle. As you slide forwards and backwards through the music the little button shoots up and down, up and down tracing the waveform. You feel its volume changing. Music with heavy banging beats has your brass button zooming up and down, so mind your fingers!

So back to the title of the article! Joey trialled the HapticWave at a research workshop and rather wanted to take one home, he loved it so much he jokingly tried distracting the researchers to get one. But he didn’t get away with it – maybe his getaway car just wasn’t fast enough!

3. An audio illusion, and an audiovisual one

This one-minute video illustrates an interesting audio illusion, demonstrating that our brains are ‘always using prior information to make sense of new information coming in’.

The McGurk Effect

You can read more about the McGurk effect on page 7 of issue 5 of the CS4FN magazine, called ‘The Perception Deception‘.

 

4. Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing (13 December 2021)

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle (14 December 2021)

 

CS4FN Advent – Day 15 – a candle: optical fibre, optical illusions (15 December 2021)

 

CS4FN Advent – Day 16: candy cane or walking aid: designing for everyone, human computer interaction – this post

 

 

 

CS4FN Advent – Day 15 – a candle: optical fibre, optical illusions

After yesterday’s tinsel image inspiring a cable / broadband speeds themed post, today’s CS4FN Christmas Computing Advent Calendar picture of a candle has of course put me in mind of optical fibre, then that eminded me of optical illusions, so this is a light-hearted (sorry) look at those, shining a torch (or candle) into the CS4FN archives.

A candle

We’re now more than halfway through our advent calendar, having posted something every day for the last 15 days. Do we have enough material for the next 10 days? You betcha 🙂 CS4FN has been running for 16 years and we’ve produced 27 magazines for subscribing UK schools (they’re free, get your teacher to subscribe for next year’s magazine) and a whole load of other booklets and posters etc. We’ve been busy!

 

The optical pony express

by Paul Curzon, QMUL. This article originally appeared on the CS4FN website.

Read about the change in speeds in communications, from letters via pony express, to Morse via telegraph wires, then telephones via copper wires, and modern digital computing – and now at the speed of light via optical fibre.

The optical pony express

 

Illusions – The CS4FN Eye

by Paul Curzon, QMUL. This article originally appeared on our A Bit of CS4FN website.

Optical illusions tell us about how our brains work. They show that our brains follow rules that we cannot switch off.

12.ouchieye

Stare at the picture, moving your head a little as you do. The middle circle floats around as though it is not part of the rest of the eye. It isn’t moving of course. It was created by the Japanese artist Hajime Ouchi.

Your brain is doing some amazing tricks – turning the light hitting your eye into an understanding of the world around you. Knowing what is near and what is far, and whether there is movement, are things that all animals must do quickly (especially when a tiger is near rather than far!)

To work things out your brain makes some guesses. It has built in rules that spot patterns. One rule helps us guess if something is moving up and down. Another spots side to side movement.

The patterns in this picture trigger those rules, telling you there are two separate objects. The rules that allow your brain to make sense of the world quickly are telling you the wrong thing, and you cannot stop it happening!

Programs that allow computers to “see” like we do have to do more than record things like a camera. They need to make sense of what is there. They need to be able to tell objects apart. A driverless car needs to tell if that blotch of darkness is a pedestrian or just a shadow.

Machine learning is one way to do this. The computer learns rules about patterns in the data it records just as we do. If they do it well robots of the future may be fooled by the same optical illusions that we are.

 

Answer to yesterday’s puzzle

 

The creation of this post was funded by UKRI, through grant EP/K040251/2 held by Professor Ursula Martin, and forms part of a broader project on the development and impact of computing.

 

Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing (13 December 2021)

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle (14 December 2021)

 

CS4FN Advent – Day 15 – a candle: optical fibre, optical illusions – this post

 

 

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle

Today’s CS4FN Christmas Computing Advent Calendar is showing a picture of shiny tinsel, which reminds me a bit of computer cables. At least, enough to theme this post around broadband speeds 🙂

A piece of shiny tinsel.

 

Did you know?

Only two letters were transmitted over the Internet before it crashed for the first time. The Internet was born on 20 October 1969 with the first transmission of data sent from a computer at the University of California to another one at Stanford, near San Francisco. Only two letters L and O were sent – the system crashed when the G of LOGIN was entered.

Why is your Internet so slow?

by Paul Curzon, QMUL. This article was originally published on the CS4FN website.

The Internet is now so much a part of life that, unless you are over 50, it’s hard to remember what the world was like without it. Sometimes we enjoy really fast Internet access, and yet at other times it’s frustratingly slow! So the question is why, and what does this have to do with posting a letter, or cars on a motorway?

The communication technology that powers the Internet is built of electronics. The building blocks are called routers, and these convert the light-streams of information that pass down the fibre-optic cables into streams of electrons, so that electronics can be used to switch and re-route the information inside the routers.

Enormously high capacities are achievable, which is necessary because the performance of your Internet connection is really important, especially if you enjoy online gaming or do a lot of video streaming. Anyone who plays online games would be familiar with the problem: opponents apparently popping out of nowhere, or stuttery character movement.

So the question is – why is communicating over a modern network like the Internet so prone to odd lapses of performance when traditional land-line telephone services were (and still are) so reliable? The answer is that traditional telephone networks send data as a constant stream of information, while over the Internet, data is transmitted as “packets”. Each packet is a large group of data bits stuck inside a sort of package, with a header attached giving the address of where the data is going. This is why it is like posting a letter: a packet is like a parcel of data sent via an electronic “postal service”.

But this still doesn’t really answer the question of why Internet performance can be so prone to slow down, sometimes seeming almost to stop completely. To see this we can use another analogy: the flow of packet data is also like the flow of cars on a motorway. When there is no congestion the cars flow freely and all reach their destination with little delay, so that good, consistent performance is enjoyed by the car’s users. But when there is overload and there are too many cars for the road’s capacity, then congestion results. Cars keep slowing down then speeding up, and journey times become horribly delayed and unpredictable. This is like having too many packets for the capacity in the network: congestion builds up, and bad delays – poor performance – are the result.

Typically, Internet performance is assessed using broadband speed tests, where lots of test data is sent out and received by the computer being tested and the average speed of sending data and of receiving it is measured. Unfortunately, speed tests don’t help anyone – not even an expert – understand what people will experience when using real applications like an online game. Electronic engineering researchers at Queen Mary, University of London have been studying these congestion effects in networks for a long time, mainly by using probability theory, which was originally developed in attempts to analyse games of chance and gambling. In the past ten years, they have been evaluating the impact of congestion on actual applications (like web browsing, gaming and Skype) and expressing this in terms of real human experience (rather than speed, or other technical metrics). This research has been so successful that one of the Professors at Queen Mary, Jonathan Pitts, co-founded a spinout company called Actual Experience Ltd so the research could make a real difference to industry and so ultimately to everyday users.

For businesses that rely heavily on IT, the human experience of corporate applications directly affects how efficiently staff can work. In the consumer Internet, human experience directly affects brand perception and customer loyalty. Actual Experience’s technology enables companies to manage their networks and servers from the perspective of human experience – it helps them fix the problems that their staff and customers notice, and invest their limited resources to get the greatest economic benefit.

So Internet gaming, posting letters, probability theory and cars stuck on motorways are all connected. But to make the connection you first need to study electronic engineering.

 

Today’s puzzle

Download a printable version

Festive kriss-kross puzzle.

The 11 words to fill in the squares in the puzzle above are: Advent, Bauble, Cards, Chimney, Decorations, Presents, Reindeer, Sleigh, Snowman, Stocking, Tree. Answer tomorrow.

From an earlier puzzle “You might wonder “What do these kriss-kross puzzles have to do with computing?” Well, you need to use a bit of logical thinking to fill one in and come up with a strategy. If there’s only one word of a particular length then it has to go in that space and can’t fit anywhere else. You’re then using pattern matching to decide which other words can fit in the spaces around it and which match the letters where they overlap. Younger children might just enjoy counting the letters and writing them out, or practising phonics or spelling.”

 

Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing (13 December 2021)

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle (14 December 2021) – this post

 

 

 

CS4FN Advent – Day 13: snowflakes – make your own six-sided hexahexaflexagon with our templates

The picture for today’s door of the CS4FN Christmas Computing Advent Calendar is a snowflake and, inspired by its six-sides, this post is celebrating the similarly six-sided (and six-faced) hexahexaflexagon.

A snowflake in a blue circle

A hexahexaflexagon is a strip of paper cleverly folded to hide and then reveal six hexagonal faces within it. You pinch and flex them to reveal another face, as shown in the video below. It’s effectively a Möbius strip.

The name references a hexagonal shape which is flexed to show a new face (‘flexagon’) and the hexa-hexa bit just means each face has six sides and there are six faces.

An unfolded hexahexaflexagon design.

Flexagons were discovered in the late 1930s by a British maths student (Arthur Stone) who’d arrived at Princeton University with a binder / folder from home and discovered that American paper was too large to fit in. He cut off the excess strips and ‘doodled’ with them by folding them into different shapes, then involving his classmates in developing them.

There are lots of ways to make them but we’ve created some templates to help. You can print our hexahexaflexagons or make and decorate your own from scratch. Ours depict Father Christmas looking for the six presents he’s lost among the different faces but there’s a blank template if you’d like to design your own.

Of course there’s some computer science and maths behind these too – we have a free PDF booklet which you can download from the link below, called Computational Thinking: HexaHexaFlexagon Automata.

 

Print or make your own hexahexflexagon

 

 

The six faces of our ready-to-print hexahexaflexagon.

 

Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing – this post

 

 

 

CS4FN Advent Calendar – bonus material: HexaFestiveFlexagons to make and colour in

Father Christmas has lost six of his presents inside this flexagon. The first two are easy to find but can you uncover the other four?

There’s a gift on side one, and another if you turn the hexahexaflexagon over. Another 4 to find inside the flexagon.

 

Print and make your own hexahexaflexagon and help Father Christmas find the missing gifts.

  1. Print (or draw) your flexagon
  2. Cut it out, then fold it following the instructions
  3. Find all of Father Christmas’ lost gifts by pinching and folding the flexagon to reveal the hidden faces
Folding a hexahexaflexagon – pinch and flex. Three sides are shown, there are another three inside the folds.

A hexahexaflexagon is a six sided shape (hexagon) which also has six faces in total (hexa-hexa) and which can flex and fold to show a new face (flexagon). They are fun to make and play with but can also be used to learn some computational thinking. To get to each face or side you may need to follow a variety of paths, you can’t always get to every face from every other face. The sides you can reach depend on the sides you currently have visible – it’s a ‘finite state machine’ and you can create a map to describe how you navigate around your hexahexaflexagon. See our page on Computational Thinking: HexaHexaFlexagon Automata and download our free booklet (PDF) to find out more. We definitely recommend this as an end-of-term classroom activity.

Computational Thinking: HexaHexaFlexagon Automata

Table of Contents
A. For people who want a ready-coloured hexahexaflexagon – print and go
B. For people who want to colour in their own hexahexaflexagon – print & colour in
C. For people who want to design their own hexahexaflexagon on a computer
D. For people who don’t have a printer or want to design a hexahexaflexagon from scratch
E. Useful videos

 

A. For people who want a ready-coloured hexahexaflexagon

• Print this PDF file: Father Christmas coloured hexahexaflexagon
• Use these instructions: CS4FN How to fold a hexahexaflexagon

 

 

 

B. For people who want to colour in their own hexahexaflexagon

• Print this PDF file: Father Christmas black and white hexahexaflexagon to colour (this contains a guide if you want each of the six faces to have its own colour)
• Use these instructions: CS4FN How to fold a hexahexaflexagon – black and white

 

 

 

C. For people who want to design their own hexahexaflexagon on a computer

• Print this PDF file: CS4FN blank hexahexaflexagon – design your own
• Use these folding instructions: CS4FN How to fold a hexahexaflexagon – black and white
• just the triangles – .svg / .png

It may be easier to make the flexagon first then colour it in, then it’s easier to see which triangle is on which face, but the printable does have instructions in if you want to make one that will ‘work’ once folded.

 

D. For people who don’t have a printer or who want to create one from scratch

• Read the instructions here: – CS4FN How to create a hexahexaflexagon from scratch
• Use these folding instructions: CS4FN How to fold a hexahexaflexagon – black and white
• Useful website for calculating the height needed for an equilateral triangle (if you want to create hexahexaflexagons on different sizes of paper) https://www.omnicalculator.com/math/equilateral-triangle

 

E. Useful videos

Above: CS4FN’s Paul Curzon demonstrates how to fold one (note that the direction of the first round of folding is different from the written instructions above, though it doesn’t matter if you go from A to B or B to A).

Above: Vi Hart has an excellent series of hexaflexagon and hexahexaflexagon videos including how they were discovered.

 

A picture showing all six faces of the hexahexaflexagon made for the CS4FN Christmas Computing Advent Calendar.

Part of our CS4FN Christmas Computing Advent Calendar.

CS4FN Christmas Computing Advent Calendar

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors

Computer memory molecular style, memristors, maths puzzle answer and a “20 questions” activity

Remember remember the 24th of December – as that’s the day to hang out your Christmas stocking! That’s the picture for today’s door on the CS4FN Christmas Computing Advent Calendar and I’ve made the somewhat stretched link between a stocking as a store for your presents and computer memory as a store for all your data.

A Christmas stocking. No presents though. Yet…

If your own memory needs a prod you can find a list of our previous posts at the end of this one.

Molecular memory

by Charlie Tizzrd, QMUL. This article was originally published on the CS4FN website.

What happens when computers need so much memory that they start to test the laws of physics? Charlie Tizzard investigates.

A new way to store data in individual molecules might put some life back into an old law of computing. Back in 1965, the founder of Intel, Gordon Moore, noticed that computer chips doubled their performance about every 18 months. Not only was he right in 1965, he kept on being right. Ten, twenty, even thirty years later, chip power still doubled every 18 months. This observation was so strong that it began to seem like a law of nature. It was named “Moore’s law” after Gordon Moore himself.

But some experts believe that Moore’s law is beginning to waver. As electronics continue to get smaller and smaller they are pushing the law to the limit. Electronics are now so small that even the laws of physics are even getting in the way. An esteemed physicist, Michio Kaku, said that “we already see a slowing down of Moore’s law. Computing power simply cannot maintain its rapid exponential rise using standard silicon technology.”
What to do?

Unless we move away from silicon-based storage in computing, we will run into some serious issues in the near future. Fortunately, scientists and engineers are experimenting with alternative ways of storing data. One way is to use molecules whose atoms can be shifted around within them. Storing data is all about making physical changes to something. That means you can put information in molecules by representing it as different atomic states. Best of all, those states can be changed and read by the same technology we have today: changes to the amount of electricity the molecules conduct.

Our only problem is that this idea works great inside a lab setting, but it can be difficult in the real world. First of all, molecular storage needs to be mass produced, but so far it’s specialised equipment built only in labs. Not only that, but up until now the molecules had to be kept at almost absolute zero (that’s -273°C) in order to work. But now an international team of researchers at MIT led by Jagadeesh Moodera have pioneered a new technique that allows the molecules to be kept at roughly the freezing point of water. In physics that’s practically room temperature.

Even more importantly, the molecules, which previously had to be sandwiched between two electrical conductors, only require one conductor in the MIT setup. That will make mass manufacturing a lot simpler and cheaper for companies. “This is only the tip of tip of the iceberg” says Moodera, so don’t be surprised if you are using chemicals for storing your photos in the future!

 

Do you remember the birth of the memristor?

by Paul Curzon, QMUL. This article was originally published on the CS4FN website.

A memristor – photo from Wikimedia Commons.

Electronics! It’s all been done long ago, hasn’t it? Resistors, transistors, capacitors, and inductors: all invented. See. Done it, filled in the worksheet, nothing else to discover…but did you miss the birth of the memristor?

In 2008 a new member of the electronics family was born. It had been discussed in theory as the missing link. It was mathematically possible, but never actually built till electronic engineers at Hewlett Packard used nanotechnology to bring it into existence.

Memristors are resistors with memory. Doh! Clever name! It can work as a data store, being either off or on, but it can store this information without any power too. This ability to store binary data (1s and 0s) with no drain on a battery, combined with its tiny, nanotechnology size means that memristors can store more data than any normal hard drive, and can be accessed as quickly as RAM – the kind of memory computers currently use. That means that in the future computers may be able to store more, start faster and be eco friendly too.

Building brains? That would be amazing enough but it turns out that the memistor has another trick up its nano-sleeve. Rather than working in digital mode, saving on/off (1,0) data like normal computer components, it can also hold values in between! The values it holds change every time the memristor receives an electrical signal, which is exactly what happens in the neurones of our brain as we learn. In the future networks of memristors could mimic the way our brains work, storing the things they learned from their electronic experiences. That would open up the possibility of a compact, low power way to build artificial intelligences.

Not bad for a humble little addition to the family of electronic components. See what you can miss is you don’t pay attention!

 

2. Today’s activity – the 20 questions game

The game 20 Questions, as the name suggests, involves trying to guess which famous person someone is thinking about by asking a maximum of 20 questions, all of which can be answered by YES or NO. The trick – of course – is to use good questions.

You’d be there all day if you kept asking them “Is it this person?”, “Is it that person?”. Those types of questions don’t chip away at the enormity of ~8 billion or so possibilities. Better questions might include “Are they alive?”, “Are they European?”. A yes or no answer to those questions tells you much more and helps narrow things down.

The game is a great way to learn about information theory and how the best questions are ones that split the options in half (roughly!). Most of the 8 billion people on Earth aren’t that famous, let’s assume it’s around 1 million people (because the maths is handy if we do!). If each of your questions divides a population of famous people in half each time and we start with one million people, how many questions do you need to ask before you get down to one person?

Or, to put it another way 2 (dividing in half) to the power of 20 (the 20 questions) or 220 gives 1,048,576 people (or items).

We developed an activity for teachers and students to do in the classroom (you can do it at home too) that uses the game to explore different search algorithms and improving how computers (and we) find information. It was number 4 in our 10 most popular downloads last year.

Use the activity to find out more about these computing concepts, while seeing how efficiently you can guess what someone else is thinking about.

  • computational thinking
  • linear search
  • binary search
  • divide and conquer
  • comparing algorithms

The 20-questions Activity

 

3. Answer to yesterday’s puzzle

 

The creation of this post was funded by UKRI, through grant EP/K040251/2 held by Professor Ursula Martin, and forms part of a broader project on the development and impact of computing.

 

4. Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021) – this post

 

 

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof

A mathematical proof and a maths puzzle (but no hard sums, promise).

Thank you to everyone who’s been reading our Advent Calendar and said nice things about it and shared it with others. If you’re new to our pages you can see all our previous posts at the end.

We’re doing a post every day from the 1 – 25 December, loosely connected (if we can manage it!) to the theme suggested by the picture on the CS4FN Christmas Computing Advent Calendar.

Today’s picture on the Advent Calendar door is a Christmas pudding. Thanks to the phrase “the proof of the pudding is in the eating” (which I think means you have to eat all the chocolate puddings to know if they’re any good) I have chosen to match this picture with one of the CS4FN articles from the archives that is all about PROOF. Sadly we don’t seem to have any articles about pudding.

People sometimes pour brandy on Christmas puddings and set fire to it but this one has been iced instead and is not a fire hazard.

 

1. Proof without words

by Paul Curzon, QMUL. This article was originally published on the CS4FN website.

A graphical representation of squaring numbers

Graphic news images often help sway public opinion. Images of famine in Africa led to LiveAid, a massive relief effort in 1985. Images from war zones of civilians can be disturbing enough that war leaders lose or gain political support as a result (depending on who did the bad stuff). Images can have far more power than words to argue a case … to persuade.

Mathematical proofs are just arguments intended to persuade too. They aim to leave no element of doubt that some fact is true, not for emotional reasons but by logic. Mathematicians use mathematical notation – special symbols used in precise ways – to represent things in their proofs. That’s just a way of making sure the arguments are precise, with no room for doubt. Sometimes that can make them seem arcane and difficult to follow, though that’s only until you’ve learnt the mathematical language being used.

Mathematical proofs don’t have to use words and symbols though. In fact people have been presenting proofs as pictures at least since the Ancient Greeks, and just as with news images a diagrammatic proof can be much more persuasive. Sometimes just by looking at a diagram the truth of a fact can become obvious.

For example, here is a mathematical ‘fact’ we might want to prove:

“The square of any number is equal to the sum of consecutive odd numbers.”

That may sound a bit hairy. To get even hairier (if you aren’t a mathematician), we can write this precisely in mathematical notation as:

n2 = 1 + 3 + 5 + …+ (2n – 1)

Don’t worry about the notation though. Just look at the pictures. They show what we mean by the fact and should persuade you it’s true.

The square of a number can be drawn as a picture of dots in a square. In other words one way to work out 102, say, is to create a square of dots with sides of length 10 and then count the dots. That’s why it’s called ‘squaring’!

One way to draw the dots to make up a square is as follows. First draw one dot in the corner, then draw three dots in an L-shape round it, then draw 5 dots in an L-shape round that…and keep going. Add a new L-shape (including the first dot) 10 times, say, once for each dot along the side, and you get a square of size 10 with 100 dots altogether. Notice that at every step you still have a square, though. Also notice that each L-shape is 2 bigger than the one before. That’s because you can make it by adding one dot on the end of each arm of the last L-shape.

That means the number of dots in a square can be calculated by adding a sequence of odd numbers, one for each L-shape added: 1 + 3 + 5 + … As you add L-shapes you work up through squares of all sizes, so all squares can be made by adding odd numbers in this way.

We’ve just explained it in words, but actually it’s all in the picture, so it’s possible to see without needing the words at all.

At least it may be possible for a person to see perhaps, but what about a computer? Could a computer ‘see’ a proof from a diagram? Computers are now very good at helping humans do logical proof using mathematical notation – after all they work themselves by pushing ‘symbols’ about and following rules blindly, which is all logical proof is. Seeing a proof in a diagram is different altogether though…or is it?

Mateja Jamnik, of the University of Cambridge has been tackling this problem. In fact her system, DIAMOND, can already check diagrammatic proofs created by a person to see if they really do convince. With DIAMOND you could, for example, take a series of L shape pictures like ours above and build them up step-by-step giving squares of different sizes. The system can then pull out the structure of this step-by-step proof and from that automatically obtain the equation that it proves.

DIAMOND needs a person to develop a diagrammatic proof for it to check. In the future, if Mateja has her way, the computers will be devising new diagrammatic proofs themselves that then convince we humans.

2. Today’s puzzle – Logic and Proof FUNdamentals

(This text, by Paul Curzon, was originally published over several pages at the CS4FN website)

It is often said that being good at Maths is important for Computer Scientists. So what’s the link? Well a lot of the more obviously fun sides of maths are actually computer science too, like how to do puzzles such as Rubik’s Cubes, puzzles about weird and wonderful characters crossing rivers, how to win at strategy games, and doing Sudoku. The Maths you do in solving a Sudoku is the same kind of reasoning as that behind getting computer programs to work.

It is not so much the actual Maths you learn at school that is important. It is more that a similar way of thinking is important: logical reasoning. Doing Maths at school is one good way to start to learn how to think that way. So if you are good at Maths you will probably be good at Computer Science, though (using a bit of logical reasoning) that doesn’t mean the opposite follows of course.

Kakuro, Logic and Computer Science

To be a good computer scientist you have to enjoy problem solving. That is what it’s all about: working out the best way to do things. You also have to be able to think in a logical way: be a bit of a Vulcan. But what does that mean? It just means being able to think precisely, extracting all the knowledge possible from a situation just by pure reasoning. It’s about being able to say what is definitely the case given what is already known…and it’s fun to do. That’s why there is a Sudoku craze going on as I write. Sudoku are just pure logical thinking puzzles. Personally I like Kakuro better. They are similar to Sudoku, but with a crossword format.

What is a Kakuro?

A Kakuro is a crossword-like grid, but where each square has to be filled in with a digit from 1-9 not a letter. Each horizontal or vertical block of digits must add up to the number given to the left or above, respectively. All the digits in each such block must be different. That part is similar to Sudoku, though unlike Sudoku, numbers can be repeated on a line as long as they are in different blocks. Also, unlike Sudoku, you aren’t given any starting numbers, just a blank grid.

Where does logic come into it? Take the following fragment:

There is a horizontal block of two cells that must add up to 16. Ways that could be done using digits 1-9 are 9+7, 8+8 or 7+9. But it can’t be 8+8 as that needs two 8s in a block which is not allowed so we are left with just two possibilities: 9+7 or 7+9. Now look at the vertical blocks. One of them consists of two cells that add up to 17. That can only be 9+8 or 8+9. That doesn’t seem to have got us very far as we still don’t know any numbers for sure. But now think about the top corner. We know from across that it is definitely 9 or 7 and from down that it is definitely 9 or 8. That means it must be 9 as that is the only way to satisfy both restrictions.

A Kakuro for you to try

Here is a full Kakuro to try. The answer will be in tomorrow’s post.

Being able to think logically is important because computer programming is about coming up with precise solutions that even a dumb computer can follow. To do that you have to make sure all the possibilities have been covered. Reasoning very much like in a Kakuro is needed to convince yourself and others that a program does do what it is supposed to.

 

Printer friendly version as PDF.

 

3. Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021) – this post

 

 

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses

Chatbots, knowing where your files are, and winning at noughts and crosses with artificial intelligence.

Welcome to Day 10 of our CS4FN Christmas Computing Advent Calendar. We are just under halfway through our 25 days of posts, one every day between now and Christmas. You can see all our previous posts in the list at the end.

Today’s picture-theme is Holly (and ivy). Let’s see how I manage to link that to computer science 🙂

Some holly with red berries

1. Holly – or Alexa or Siri

In the comedy TV series* Red Dwarf the spaceship has ‘Holly’ an intelligent computer who talks to the crew and answers their questions. Star Trek also has ‘Computer’ who can have quite technical conversations and give reports on the health of the ship and crew.

People are now quite familiar with talking to computers, or at least giving them commands. You might have heard of Alexa (Amazon) or Siri (Apple / iPhone) and you might even have talked to one of these virtual assistants yourself.

When this article (below) was written people were much less familiar with them. How can they know all the answers to people’s questions and why do they seem to have an intelligence?

Read the article and then play a game (see 3. Today’s Puzzle) to see if you think a piece of paper can be intelligent.

Meet the Chatterbots – talking to computers thanks to artificial intelligence and virtual assistants

 

*also a book!

 

2. Are you a filing cabinet or a laundry basket?

People have different ways of saving information on their computers. Some university teachers found that when they asked their students to open a file from a particular directory their students were completely puzzled. It turned out that the (younger) students didn’t think about files and where to put them in the same way that their (older) teachers did, and the reason is partly the type of device teachers and students grew up with.

Older people grew up using computers where the best way to organise things was to save a file in a particular folder to make it easy to find it again. Sometimes there would be several folders. For example you might have a main folder for Homework, then a year folder for 2021, then folders inside for each month. In the December folder you’d put your december.doc file. The file has a file name (december.doc) and an ‘address’ (Homework/2021/December/). Pretty similar to the link to this blog post which also uses the / symbol to separate all the posts made in 2021, then December, then today.

Files and folders image by Ulrike Mai from Pixabay. Each brown folder contains files, and is itself contained in the drawer, and the drawer is contained in the cabinet.

To find your december.doc file again you’d just open each folder by following that path: first Homework, then 2021, then December – and there’s your file. It’s a bit like looking for a pair of socks in your house – first you need to open your front door and go into your home, then open your bedroom door, then open the sock drawer and there are your socks.

What your file and folder structure might look like.

Younger people have grown up with devices that make it easy to search for any file. It doesn’t really matter where the file is so people used to these devices have never really needed to think about a file’s location. People can search for the file by name, by some words that are in the file, or the date range for when it was created, even the type of file. So many options.

The first way, that the teachers were using, is like a filing cabinet in an office, with documents neatly packed away in folders within folders. The second way is a bit more like a laundry basket where your socks might be all over the house but you can easily find the pair you want by typing ‘blue socks’ into the search bar.

Which way do you use?

In most cases either is fine and you can just choose whichever way of searching or finding their files that works for you. If you’re learning programming though it can be really helpful to know a bit about file paths because the code you’re creating might need to know exactly where a file is, so that it can read from it. So now some university teachers on STEM (science, technology, engineering and maths) and computing courses are also teaching their students how to use the filing cabinet method. It could be useful for them in their future careers.

Want to find out more about files / file names / file paths and directory structures? Have a look at this great little tutorial https://superbasics.beholder.uk/file-system/

As the author says “Many consumer devices try to conceal the underlying file system from the user (for example, smart phones and some tablet computers). Graphical interfaces, applications, and even search have all made it possible for people to use these devices without being concerned with file systems. When you study Computer Science, you must look behind these interfaces.

You might be wondering what any of this has to do with ivy. Well, whenever I’ve seen a real folder structure on a Windows computer (you can see one here) I’ve often thought it looked a bit like ivy 😉

Creeping ivy at Blackheath station in London.

Further reading

File not found: A generation that grew up with Google is forcing professors to rethink their lesson plans (22 September 2021) The Verge

 

 

3. Today’s puzzle

Print or write out the instructions on page 5 of the PDF and challenge someone to a game of noughts and crosses… (there’s a good chance the bit of paper will win).

The Intelligent Piece of Paper activity.

 

4. Yesterday’s puzzle

The trick is based on a very old puzzle at least one early version of which was by Sam Lloyd. See this selection of vanishing puzzles for some variations. A very simple version of it appears in the Moscow Puzzles (puzzle 305) by Boris A. Kordemsky where a line is made to disappear.

In the picture above five medium-length lines become four longer lines. It looks like a line has disappeared but its length has just been spread among the other lines, lengthening them.

If you’d like to have a go at drawing your own disappearing puzzle have a look here.

 

5. Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021) – this post

 

 

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle

Computing- and food-themed post on cookies and spam + a puzzle.

Welcome to Day 9 of our CS4FN Christmas Computing Advent Calendar. Every day between now and Christmas we’ll publish a post about computer science with a puzzle to print and solve. You can see all our previous posts in the list at the end.

Today’s post is inspired by the picture on the advent calendar’s door – a gingerbread man, so we have a food-themed post. Well… food-ish.

Festive gingerbread man, wearing a mask. Safety first!

1. Cookies, but not the biscuit kind

Imagine you have a Christmas gift voucher and want to spend it in an online shop. You visit the website and see an item you’d like so you click ‘add to basket’ and then look for some other things you’d like to buy. You click on another item to find out more about it but suddenly your basket is empty! Fortunately this doesn’t usually happen thanks to cookies, which are tiny computer files that can make your website visit run smoothly.

Websites ask you if they can put these cookies on your computer. If you say ‘yes’ that lets them see that you are the same person as you add new things to your basket. It would be no use if you added your second item and the website decided that you were now a completely different person. Some cookies help the organisation know that you’re still you, even when you’re viewing lots of different pages on their website.

Cookie image by congerdesign from Pixabay

Other cookies mean that you don’t have to keep logging in every time you click on a new page within the website. It would be very annoying if you had to do that.

Some cookies are there to help the organisation itself. They let them see what people are clicking on when they’re on the organisation’s website, and what path they follow as they visit different pages. They can also tell what device someone is using (a phone or a computer) so they can make sure the information is set to be the right size on their screen.

If people are logged in then the website knows who they are. Because of this, organisations have to be very careful about how they use this information, to protect their visitors’ privacy. If they don’t take care then they are breaking the law and can be fined a lot of money.

Further reading

Cookies (no publication date given) – from the ICO – the Information Commissioner’s Office.

 

 

2. The recipe for spam

These days when people talk about “spam” they are talking about unwanted emails from strangers. The word spam comes from a tinned meat product which, because of a comedy sketch by Monty Python, now also means “email messages that no-one can avoid”.

by Paul Curzon, QMUL. This post was originally published on the CS4FN website.

Fighting spam

Monitor screen showing spam in the mailbox

Shutting down spammers is tough for the authorities, so the internet’s arteries go on getting plugged up by spam. The best strategy against it so far seems to be filtering out junk emails from your inbox. Lots of early spam filtering relied on keeping lists of words that appear in spam and catching emails that contained them, but there were plenty of problems. For one thing, certain words that turn up in spam also appear sometimes in normal emails, so perfectly innocent messages sometimes ended up in the spam filter. What’s more, spammers have ways of eluding filters that simply check words against a list. Just me55 a-r-0-u-n-d w1th teh sp£lling.

Finally a simple but ingenious idea surfaced: instead of trying to keep a list of spammy words, why not try and teach computers to recognise spam for themselves? There’s a whole branch of maths about probability that researchers began to apply to spam, and a programmer called Paul Graham made the strategy famous in 2002 when he wrote an essay called A Plan for Spam.

Spammy maths

Paul Graham suggested that you could analyse the words you get in a sample of your email to see what the chances are that a particular word would appear in your real messages. You could do the same with a sample from your spam. Then you could look up any word in a new message and see whether it’s likely to be spam or your real email.

Of course, one word’s not enough to base your conclusion on, so Paul’s filter chose the fifteen most interesting words to look at. What that meant was that it grabbed the biggest clues to look at – words that, statistically, had the best chance of being in either spam or real mail, but not both. Then it used those clues to figure out the overall chance that an email is spam. It did this with an equation called Bayes’ theorem, which tells you how to figure out the chances of something being true given a set of facts. In this case Bayes’ theorem figures out the chances of a message being spam given the set of words in it.

What’s brilliant about the statistical approach is that not only does the computer learn as it goes on, meaning it keeps up with spammers’ tricks automatically, it can learn what words are normal for each person’s email, so scientists working on Viagra wouldn’t have to worry about all their emails going in the bin.

On guard online

Spam filters now work well enough that you can make your inbox pretty safe from the porky hordes of messages trying to invade. Wonderful news for the 99% of us who don’t have any use for dodgy meds, fake fashions and pyramid scams. As long as people keep buying into spam and the small group of overlords keeps turning computers into zombies, we’ll need to keep our defences up.

 

3. Today’s puzzle – the melting snowman

A picture showing several snowmen, drawn by Paul Curzon.

Instructions

One of the snowmen keeps disappearing! Is it melting or just flying
away, and which one is it?

Cut out the picture along the straight black lines, to give three
rectangular pieces. Then follow the simple algorithm and see the
snowman disappear before your eyes.

1. Put the three pieces together in the original positions to make the picture.
2. Count all the snowmen.
3. Swap the position of the top two pieces over so the top and bottom halves of the snowmen line up again
4. Count the snowmen again.

One snowman has disappeared!

Put the pieces back and you will find it reappears.

The explanation and answer will arrive in tomorrow’s (blog) post 🙂

 

4. Answer to yesterday’s puzzle

Here’s the answer to Daniel’s puzzle.

 

5. Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021) – this post

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, Right to Repair & another computing puzzle

Tim Berners-Lee, Right to Repair, and a maths puzzle.

Welcome to Day 8 of our CS4FN Christmas Computing Advent Calendar. It features a computing-themed post every day in December until Christmas Day. All the blog posts in the Advent Calendar so far have been inspired by the picture on the ‘door’ – and today’s post is also inspired by the picture, which is of a Christmas present.

Presents are something you give freely to someone, but they’re also something you hide behind wrapping paper. This post is about a gift and also about trying to uncover something that’s been hidden. Read on to find out about Tim Berners-Lee’s gift to the world, and about the Restart Project who are working to stop the manufacturers of electronic devices from hiding how people can fix them. At the bottom of the post you’ll find the answer to yesterday’s puzzle and a new puzzle for today, also all of the previous posts in this series. If you’re enjoying the posts, please share them with your friends 🙂

A present in blue wrapping paper with a large green bow.

 

1. “This is for everyone” – Tim Berner’s Lee

Audiences don’t usually cheer for computer scientists at major sporting events but there’s one computer scientist who was given a special welcome at the London Olympics Opening Ceremony in 2012.

Tim Berners-Lee invented the World Wide Web in 1989 by coming up with the way for web pages to be connected through links (everything that’s blue and clickable on this page is a link). That led to the creation of web browsers which let us read web pages and find our way around them by clicking on those links. If you’ve ever wondered what “www” means at the start of a link it’s just short for World Wide Web. Try saying “www” and then “World Wide Web” – which takes longer to say?

Tim Berners-Lee didn’t make lots of money from his invention. Instead he made the World Wide Web freely available for everyone to use so that they could access the information on the web. Unless someone has printed this onto paper, you’re reading this on a web browser on the World Wide Web, so three cheers Tim Berners-Lee.

In 2004 the Queen knighted him (he’s now Sir Tim Berners-Lee) and in 2017 he was given a special award, named after Alan Turing, for “inventing the World Wide Web and the first web browser.”

Below is the tweet he sent out during the Olympics opening ceremony.

 

 

Further reading

The Man Who Invented The Web (24 June 2001) Time
“I Was Devastated”: Tim Berners-Lee, the Man Who Created the World Wide Web, Has Some Regrets (1 July 2018) Vanity Fair

 

2. Do you have the right to repair your electronic devices?

A ‘black box’ is a phrase to describe something that has an input and an output but where ‘the bit in the middle’ is a complete mystery and hidden from view. An awful lot of modern devices are like this. In the past you might have been able to mend something technological (even if it was just changing the battery) but for devices like mobile phones it’s becoming almost impossible.

People need special tools just to open them as well as the skills to know how to open them without breaking some incredibly important tiny bit. Manufacturers aren’t always very keen for customers to fix things. The manufacturers can make more money from us if they have to sell us expensive parts and charge us for people to fix them. Some even put software in their devices that stops people from fixing them!

The cost of fixing devices can be very expensive and in some cases it can actually be cheaper to just buy a new device. Obviously it’s very wasteful too.

The Restart Project is full of volunteers who want to help everyone fix our electronic devices, and also fix our relationship with electronics (discouraging us from throwing away our old phone when a new one is on the market). The project began in London but they now run Repair Parties in several cities in the UK and around the world. At these parties people can bring their broken devices and rather than just ‘getting them fixed’ they can learn how to fix their devices themselves by learning and sharing new skills. This means they save money and save their devices from landfill.

Restart also campaign for people to have the Right to Repair their own devices. They want a change in manufacturing laws to make sure that devices are designed so that the people who buy and use them can easily repair them without having to spend too much money.

 

3. Today’s puzzle

A more mathematical puzzle today. Rather than writing letters into the kriss-kross you need to write the equation and its answer.

For example 5 + 2 = as the clue gives you 5 + 2 = 7 as the answer which takes up 5 characters (note that the answer is not “seven” which also takes up 5 characters!). There are several places in the puzzle where a 5 character answer could go, but which one is the right one? Start with the clues that have only one space they can fit into (the ones with 7 symbols and 9 symbols) then see what can fit around them.

This puzzle was created by Daniel, aged 6. For an explanation of the links to computer science and how these puzzles can be used in the classroom please see the Maths Kriss-Kross page on our site for teachers. Note that the page does include the answer sheet, but no cheating, we’ll post the answer tomorrow. Also, if you don’t have a printer you can use the editable PDF linked on that page.

4. Answer to yesterday’s puzzle

 

The creation of this post was funded by UKRI, through grant EP/K040251/2 held by Professor Ursula Martin, and forms part of a broader project on the development and impact of computing.

 

5. Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021) – this post