CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks

Welcome to the second ‘window’ of the CS4FN Christmas Computing Advent Calendar. The picture on the ‘box’ was a pair of mittens, so today’s focus is on pairs, and a little bit on gloves. Sadly no pear trees though.

A pair of cyan blue Christmas mittens with a black and white snowflake pattern on each.

1. i-pickpocket

In this article, by a pair (ho ho) of computer scientists (Jane Waite and Paul Curzon), you can find out how paired devices can be used to steal money from people, picking pockets at a distance.

Credit cards denim jeans blue image by TheDigitalWay from Pixabay

A web card for the i-pickpocket article on the CS4FN website.

2. Gestural gloves

Working with scientists musician Imogen Heap developed Mi.Mu gloves, a wearable musical instrument in glove form which lets the wearer map hand movements (gestures) to a particular musical effect (pairing a gesture to an action). The gloves contain sensors which can measure the speed and position of the hands and can send this information wirelessly to a controlling computer which can then trigger the sound effect that the musician previously mapped to that hand movement.

You can watch Imogen talk about and demo the gloves here and in the video below, which also looks at the ways in which the gloves might help disabled people to make music.

Further reading

The glove that controls your cords… (a CS4FN article by Jane Waite)

3. Pair programming

‘Pair programming’ involves having two people working together on one computer to write and edit code. One person is the ‘Driver’ who writes the code and explains what it’s going to do, the other person is the ‘Navigator’ who observes and makes suggestions and corrections. This is a way to bring two different perspectives on the same code, which is being edited, reviewed and debugged in real-time. Importantly, the two people in the mini-team switch roles regularly. Pair programming is widely used in industry and increasingly being used in the classroom – it can really help people who are learning about computers and how to program to talk through what they’re doing with someone else (you may have done this yourself in class). However, some people prefer to work by themselves and pair programming takes up two people’s time instead of one, but it can also produce better code with fewer bugs. It does need good communication between the two people working on the task though (and good communication is a very important skill in computer science!).

Here’s a short video from Code.org which shows how it’s done.

4. Digital Twins

A digital twin is a computer-based model that represents a real, physical thing (such as a jet engine or car component) and which behaves as closely as possible to the real thing. Taking information from the real-world version and applying it to the digital twin lets engineers and designers test things virtually, to see how the physical object would behave under different circumstances and to help spot (and fix) problems.


5. A magic trick: two cards make a pair

You will need

  • some playing cards
  • your hands (no mittens)
  • another pair of mitten-free hands to do the trick on

Find a pack of cards and take out 15 (doesn’t matter which ones, pick a card, any card, but 15 of them). Ask someone to put their hands on a table but with their fingers spread as if they’re playing a piano. You are going to do a magic trick that involves slotting pairs of cards between their fingers (10 fingers gives 8 spaces). As you do this you’ll ask them to say with you “two cards make a pair”. Take the first pair and slot them between the first space on their left hand (between their little finger and their ring finger) and both of you say “two cards make a pair”.

The magician puts pairs of cards between the assistant’s fingers.

Repeat with another pair of cards between ring finger and middle finger (“two cards make a pair”) and twice again between middle and index, and between index and thumb – saying “two cards make a pair” each time you do. You’ve now got 8 cards in 4 pairs in their left hand.

Repeat the same process on their right hand saying “two cards make a pair” each time (but you only have 7 cards left so can only make 3 pairs). There’s one card left over which can go between their index finger and thumb.

The magician removes the cards and puts them into two piles.

Then you’ll take back each pair of cards and lay them on the table, separating them into two different piles – each time saying “two cards make a pair”. Again you’ll have one left over. Ask the person to choose which pile it goes on. You, the magician, are going to magically move the card from the pile they’ve chosen to the other pile, but you’re going to do it invisibly by hiding the card in your palm (‘palming’). To find out how to do the trick, and how this can be used to think about the ways in which “self-working” magic tricks are like algorithms have a look at the full instructions and video below.

6. Something to print and colour in

Did you work out yesterday’s colour-in puzzle from Elaine Huen? Here’s the answer.

Today’s Christmas colour-in puzzle is by Elisa Huen. A clue is “helps deliver the Christmas presents”. (The answer will be in Day 3 of the CS4FN advent calendar, tomorrow).

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.

24 thoughts on “CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks

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