Author: Paul Curzon

Granite: games for good?

Curlers sweeping in front of a stone amongst other stones.
Image by AS Photography from Pixabay

Are video games good or bad for you? One game certainly did a lot of good for Bruce Mouat. He started playing a video game called Granite when he was only 8. It is a Curling game. As an adult he leads the GB Curling team in the Olympics and is one of the best players in the world, having multiple world gold medals.

Curling is a sport requiring both physical skill, strategy and nerve. It involves sliding polished stones of super hard granite down an ice track. The aim is to try and land your stones nearest the centre of a series of concentric circles 40 or so metres away. Despite the distance, millimetre accuracy is often needed. It is also called curling because the stones do not run in a straight line but curve their way into the target, in part controlled by sweepers who sweep the ice in front of the stones to alter the curl of the path as well as the distance.

It is an incredibly strategic sport with the players having to think several moves ahead, but then having to put that strategy into practice with their skill. In that way it is very much like Snooker. That is where the video game came in. Obsessed with the video game as a child, he became outstanding at the decision making in the sport by playing the video game against his granny. The reason the video game helped was because it is more than just a game, it can just as well be called a simulation, like a flight simulator. The latter are considered so accurate that pilots train on them to gain the hours needed to become skilful controlling a plane. That is what the video game Granite does for Curling.

To work as a simulator it needs what is called a physics engine. The programmers have to code the actual physics of polished granite stones sliding on ice and of ice being swept, covering all the small differences made by ice temperature, the speed of the sweeping and so on. The programmers, who were married curlers themselves, made the physics so accurate, that everything in the game behaves as close to possible as it would in reality. That means you can really learn strategy by playing it, even if you then still have to back that by hours of practice playing real curling to gain the physical skill to land stones exactly where you want them. It also can of course help inspire people to start to play the sport in reality.

In the 2026 Olympic final Bruce and Team came away with their second Silver medal, won in consecutive Olympic games, this time beaten by Canada. Even in losing the final match, Bruce Mouat made some absolutely amazing shots, both in terms of strategy and perfect physical skill under extreme pressure.

So playing a video game can certainly be for good: when the physics is so good it acts as a simulator and so can be a way to put in the hours of practice needed to be world leading, but just for fun. So have a go at playing Granite and maybe you will also gain a love of the game and so sport, then one day become a Winter Olympian yourself. Or if you love some other game or sport and learn to program, perhaps you could code a perfect simulator for it to give future players who enjoy your game an edge in the sport.

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The Proof of Love

A pseudocode poem in a red heart: Violets are violet if roses are red and violets are blue then Life is sweet else I love you
Image by CS4FN

For Valentine’s day we created this card with a pseudocode love poem. But what does it mean? Is it a statement of love or not? Now that Valentines Day is gone and logic and rational thinking are starting to reassert themselves, here is a logical argument of what it means: an informal proof of love.

We are using our own brand of poetic pseudocode here, and what matters is the formal semantics of the language (ie mathematical meaning).

What we will do is simplify the code to code that is mathematically equivalent but far simpler, explaining the semantics as we do. We will by reasoning in a similar way to doing algebra, just replacing equals with equals.

First let’s write the poem out in more program looking notation, making clearer what are statements (actions) and expressions (things that evaluate to a value. In the English reading version we are using the verb TO BE in both ways which confuses things a little.

Let’s make clear the difference between variables (that hold values and values). The colours are all values (data that can be stored) – so we will write them in capitals: RED, BLUE, VIOLET. The flowers are variables (places to store values) so we will leave them as lowercase: violets, roses. Then the title becomes an assignment (written more formally as :=). It sets the value of variable violets to value VIOLET. (We are pedantic and believe the colour of violet flowers is violet not blue!)

What comes after the keyword IF is an expression – it evaluates to a boolean (TRUE value or FALSE value) so is referred to as a boolean expression. You can think of boolean expressions as tests – true or false questions. We will use == to indicate a true/false question about whether two things are the same value.

The other two lines are statements – think of them as print statements that print a message as the action they do.

The algorithm of the poem then is:

violets := VIOLET;
IF ((roses == RED) AND (violets == BLUE))
THEN
    PRINT "Life is Sweet"
ELSE
    PRINT "I love you"


Now let us simplify the algorithm to an equivalent version a step at a time. In the assignment of the first line, the variable violets is set to value VIOLET and then not changed, so we can substitute the value (a colour in uppercase) VIOLET for variable violets (in lowercase) where it appears, and remove the assignment. This gives a simpler version of the algorithm that does exactly the same:

IF ((roses == RED) AND (VIOLET == BLUE))
THEN
    PRINT "Life is Sweet"
ELSE
    PRINT "I love you"

Now in the boolean expression, we have the subexpression

(VIOLET==BLUE)

but these are two different values and this is asking whether they are the same or not. It evaluates to true if they are the same and FALSE if they are different. It is therefore equivalent to FALSE so the whole expression becomes:

(roses==RED) AND FALSE

The original algorithm is equivalent to 

IF ((roses == RED) AND FALSE)
THEN
    PRINT "Life is Sweet"
ELSE
    PRINT "I love you"

Now whatever X is a boolean expression (X & FALSE) will always evaluate to FALSE because it needs both to be TRUE for the whole to be TRUE. The whole boolean expression therefore simplifies to FALSE and the algorithm to:

IF (FALSE)
THEN
    PRINT "Life is Sweet"
ELSE
    PRINT "I love you"

Notice how this means it does not matter what colour the roses are at all. Whether roses are red, white, blue or something else, the algorithm result will not be affected.

The semantics of an IF statement is that it evaluates exactly one of its two statements. Where its test (boolean expression) evaluates to TRUE, it executes the first THEN branch (here the Life is Sweet branch) and ignores the other ELSE branch (the I love you branch). Where its test evaluates to FALSE it instead ignores the THEN branch completely and executes the ELSE branch.

Here the test is FALSE, so it ignores the THEN branch and is equivalent to the ELSE branch. The algorithm as a whole is exactly equivalent to the far simpler algorithm:

PRINT "I love you"


Going back to the poem, it is therefore logically completely equivalent to a poem
I Love You

We have given a mathematical proof of love! The idea though is that only computer scientists with a formal semantics (ie maths meaning) of the pseudocode language used would see it!

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Paul Curzon, Queen Mary University of London

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Can a program beatbox (using physics)?

A rapper
Image by Casey Budd from Pixabay

Can a translation program make music? It turns out they potentially can – they can beatbox! In the future perhaps Artificial Intelligences will be able to do creative beatboxing the way human beatboxers do.

Beatboxing is a kind of vocal percussion used in hip hop music. It mainly involves creating drumbeats, rhythm, and musical sounds using your mouth, lips, tongue and voice. So how on earth can Google Translate do that? Well a cunning blogger worked out a way. Once on the Google Translate page they first set it to translate from German into German (which you could do then). Next they typed the following into the translate box: pv zk pv pv zk pv zk kz zk pv pv pv zk pv zk zk pzk pzk pvzkpkzvpvzk kkkkkk bsch; Then when they clicked on the “Listen” button to hear this spoken in German. Google translate beatboxed.

So how do programs like Google Translate that turn text into speech do it? The technology that makes this possible is called ‘speech synthesis’: the artificial production of human speech.

Originally, to synthesise speech from text, words are first mapped to the way they are pronounced using special pronunciation (‘phonetic’) dictionaries – one for each language you want to speak. The ‘Carnegie Mellon University Pronouncing Dictionary’ is a dictionary for North American English, for example. It contains over 125 000 words and their phonetic versions. Speech is about more than the sounds of the words though. Rhythm, stress, and intonation matter too. To get these right, the way the words are grouped into phrases and sentences has to be taken into account as the way a word is spoken depends on those around it.

There are several ways to generate synthesised speech given its pronunciation and information about rhythm and so on. One is simply to glue together pieces of pre-recorded speech that have been recorded when spoken by a person. Machine learning provides a new way to do it – machine learning programs are trained on vast amounts of recorded speech and learn the natural way humans speak from listening to humans actually speak. That gives a way to overcome the problems of just using pronunciation dictionaries.

Another way uses what are called ‘physics-based speech synthesisers‘. They model the way sounds are created in the first place. We create different sounds by varying the shape of our vocal tract, and altering the position of our tongue and lips, for example. We can also change the frequency of vibration produced by the vocal cords that again changes the sound we make. To make a physics-based speech synthesiser, we first create a mathematical model that simulates the way the vocal tract and vocal cords work together. The inputs of the model can then be used to control the different shapes and vibration frequencies that lead to different sounds. We essentially have a virtual world for making sounds. It’s not a very big virtual world admittedly – no bigger than a person’s mouth and throat! That’s big enough to generate the sounds that match the words we want the computer to say, though.

These physics-based speech models also give a new way a computer could beatbox. Rather than start from letters and translate them into sounds that correspond to beatboxing effects, a computer could do what the creative beatboxers actually do and experiment with the positions of its virtual mouth and vocal cords to find new beatboxing sounds.

Beatboxers have long understood that they could take advantage of the complexity of their vocal organs to produce a wide range of sounds mimicking those of musical instruments. Perhaps in the future Artificial Intelligences with a creative bent could be connected to physics-based speech synthesisers and left to invent their own beatboxing sounds.

by the CS4FN team (adapted from the archive)

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The Music and AI pages are sponsored by the EPSRC (UKRI3024: DA EPSRC university doctoral landscape award additional funding 2025 – Queen Mary University of London).

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Cyber Security at the movies: Catwoman

SPOILER ALERT

A cat sat on a branch silhouetted by an orange moon
Image by bess.hamiti@gmail.com from Pixabay

The 2004 film Catwoman, starring Halle Berry as Patience Phillips (and Catwoman), has been voted as one of the worst films of all time, and has won multiple Razzies (Golden Raspberry Awards) – Halle Berry accepted hers while holding her Best Actress Academy Award. Now, however, it has a bit of a cult following. It did at least feature an African American woman as the lead, in a superhero film, possibly for the first time, and came long before Black Panther. Whether it deserves either accolades or condemnation, it certainly features some of the worst cyber-physical security seen in a film by a corporate giant. So what can we learn about cyber-physical security from the film?

The weakest link

The plot is based around the cosmetics firm Hedare Beauty and its development and product launch of a new face cream that reverses the affects of aging. Clearly, a big corporate player, the firm has a massive team at their headquarters that includes artist Patience working on PR, but also a massive research and industrial complex, developing testing and manufacturing its products. Now, cyber-criminals do not just include hackers out to cause anarchy or extort money from people, they also include people working for companies, sometimes supported by their countries, doing industrial espionage: trying to steal research and development secrets. By stealing the designs or product formulae of their competitors, such companies aim to save the massive time and development costs of doing it themselves. They then quickly produce rip-off products to steal the market. Gaining secrets can also gain criminals advantage through insider trading, buying and selling shares, so making money on the back of secret information about what is about to happen. Companies, therefore, have to take industrial espionage seriously, and that means taking cyber-security seriously too.

In Catwoman, the company, Hedare Beauty, have the normal kinds of industrial secret but also a big nasty one too, so their bosses have even more reason to put a lot of effort into security. They certainly have lots of heavies with guns looking to shoot people. However, their physical security is actually totally lax.

This is first seen when Patience’s love interest, Detective Tom Lone, merrily walks into the corporate headquarters and up to her open plan desk where she is working on the product launch to ask her for a date. How did he get in? Why isn’t anyone accompanying him in such a sensitive area especially days before a crucial launch? Where is his visitor’s pass and why isn’t he being challenged. Perhaps this can be put down to being a cop (perhaps he waived his badge about) but still someone senior should have accompanied him surely (and is returning Patience’s purse (his excuse) really a good enough reason to bypass security whoever you are?)

However, even if we let that go, later Patience has to deliver some artwork by midnight to the boss out at the industrial complex. That is where the real secrets, good and bad, are. When she gets there the foyer is locked and dark with no one on duty. In many thrillers, the heroes have to use sophisticated gadgets, amazing technical or physical skill, or subterfuge to overcome the massively sophisticated hi-tech security. Patience, by contrast, just wanders round the back looking for another way in and finds a fire door ajar. This allows her to both enter and ultimately make it to the heart of the building where secrets are being discussed. As a result she overhears (if accidentally) something she should not hear…

Perhaps the most important principle of cyber-security is that it is as weak as its weakest link. You can have all the high tech multi-factor biometric authentication systems, impossible to crack encryption, experienced and well-trained former SAS guards patrolling the foyer, and so on, but if you leave a back door open then the criminals will just ignore all your high tech security and walk in through that one back door. That is exactly what Patience does. There is no point as, for example, I have seen in real life, checking everyones access cards on a main gate, when there is an un-manned side gate. The criminals aren’t going to even try to enter through the front gate. Likewise, if you have a weak point in your cyber-security system, it does not matter how massively strong the rest is.

It is also better to think not of just cyber-security, anyway, but of cyber-physical security. The weakest links can just as easily be to do with physical security as with the computerised part – like the open door Patience found, or letting someone claiming to be a Detective to walk around anywhere in the building. Once the “Detective” is in, they can gather information to launch other attacks from other weak points they now have access to (like passwords written on post-it notes, an access card left on someone’s desk, or computers left unlocked, for example). So poor physical security can be the weak link allowing a backdoor into the computer system.

Another point from the film is that, whether cyber security or physical security, just being “inside” (a computer or a building) should not give access to everything. As you move through a building or through a computer system, there should be more locks to get through, more authentication tests to pass, with different levels of access for different people

Patience should never have got into the building, but even if she had, she shouldn’t have got further than the corridor. Luckily (!) for her, she did with the ultimate result that she gained superhuman powers and became Catwoman, so perhaps sometimes bad security is not all bad (if only in a world where people can gain superpowers from cats).

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Pseudocode Poems

A purple flower with dew drops
Image by AdelinaZw from Pixabay

Pseudocode poems are poems that work both as a poem and as an algorithm so can be read or executed. They incorporate sequencing, selection or repetition constructs and other kinds of statements to take actions. You can implement them as an actual program. Below  are our attempts. Can you write better ones?

Poems often use the ambiguity in language and aim to affect emotions. Pseudocode is intended to be precise. Programs certainly are. They do something specific and have a single precise meaning. Writing pseudocode poems that do both can be a lot of fun: just like writing normal programs is. The idea was inspired by Bryan Bilston’s poem ‘Two Paths Diverged’. Read it here or buy his wonderful book of poems, ‘ You took the last bus home’.

I am not a great poet, but here are some of my attempts at pseudocode poems to at least give you the idea. They are, in turn, based on the core control structures of Sequencing, Selection and Repetition. They also use print statements and assignments to get things done,

Sequencing

This pseudocode poem is based on sequencing: doing things one after the other.

What am I when it’s all over?

I am dire.
I am fire.

I am alone.
I am stone.

I am old.
I am cold.

We use the verb TO BE to be the equivalent of assignment: setting the value of a variable. Here it is implemented as a Python program.

def whatamI():
	"""What am I when it's all over?"""

	I = 'dire'
	I = 'fire'
	
	I = 'alone'
	I = 'stone'
	
	I = 'old'
	I = 'cold'
	
	print(I)

Selection

Here is a pseudocode poem based on selection, which is the second core control structure. It chooses between two option based on a boolean test: a true / false question. The question here is: do I love you? Dry run the algorithm or run program to find out.

Violets are violet
if roses are red and violets are blue
then
    Life is sweet
else
    I love you

Here it is implemented as a Python program (with appropriate initialisation).

def violetsareviolet():
	"""Violets are violet"""
	roses = 'red'
	violets = 'violet'
	
	if roses == 'red' and violets == 'blue':
		print('Life is sweet')
	else:
		print('I love you')

violetsareviolet()

There is also a proof of what it does/means here. Find out more about Selection based pseudocode programs via our computational literary criticism of Rudyard Kipling’s poem “If”.

Iteration or Repetition

The final kind of control structure is iteration (i.e., repetition). It is used to repeat the same lines over and over again.

Is this poem really long?

it is true
while it is true
    this is short
it is endless

Here it is implemented as a Python program.

def isthispoemreallylong():
    """Is this poem really long?"""
    it = True
    while (it == True) :
        this = 'short'
    it = 'endless'

isthispoemreallylong()

Can you work out what it does as an algorithm/program, rather than as just a normal poem? You may need a version with print statements to understand its beauty.

def isthispoemreallylong2():
    """Is this poem really long?"""
    it = True
    while (it == True) :
        this = 'short'
        print("this is " + this)
    it = 'endless'
    print("it is " + it)

isthispoemreallylong2()

The word while indicates the start of a while loop. In the pseudocode, it is a command to repeat the following statement(s). It checks the boolean expression after the body each time. Only if that boolean expression is false does it stop. In this case the body sets the variable named this to string value ‘short’. The test is about a different variable though which is not changed inside the loop, so once in the loop there is nothing that will ever change the variable it so the value of the test will always be the same. Variable it will always be True and the loop will keep setting variable this to value ‘short’, over and over again. This means the loop is a non-terminating loop. It never exits so the lines of code after it are never executed. As a program they are never followed by the computer. The variable it is never set to the value ‘endless’.

Overall the poem is short in number of lines but it is actually endless if executed. It is the equivalent of a poem that once you start reading it you never get to the end:

it is true 
check it is true 
this is short
check it is true 
this is short
check it is true 
this is short
...

Here is a more romantically inclined poem for Valentine’s day (since at the time of writing, it is coming up) again using repetition

My love for you is endless

my love is true
while my love is true
    I love you

Here it is implemented as a Python program.

def myloveforyouisendless():
"""My love for you is endless"""
my_love = True
while my_love == True:
    print('I love you')

myloveforyouisendless()
Pseudovode love poem surrounded by hearts

In the pseudocode of this poem the verb “to be” is used for two different purposes: as an assignment statement (it is true is used as a statement to mean it = True) and as a boolean expression (it is true is used as a boolean expression to mean it == True). As an assignment it is used as a command to do something. As an expression it is something representing a value: it evaluates to either true or false. Confusing these two English uses is a common mistake novices make programming, and shows one of the ways why programming languages are used with different symbols for different meanings, rather than natural languages.

Now it is your turn. Can you write a great poem that can also be executed?

Paul Curzon, Queen Mary University of London

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Answers

  1. The selection poem is about a volcano, but the answer to the question in the title is ‘cold’.
  2. Assuming you agree with me that violet flowers are violet (or at least not blue) then clearly we are compatible at least in being pedantic and you will find I love you.

If: a computational literary criticism

Image by Andrys Stienstra from Pixabay

If, by Rudyard Kipling is an inspirational poem that was voted the UKs favourite poem in the 1990s. It consists of a series of lines that start with If. What If, by Benjamin Zephaniah is a more subversive poem modelled on the original.

If statements, of course, are a really core part of programs so are these poems, given they are all about IF, algorithms? The use of If here isn’t quite the same as a pure computational one as seen in programs. For a start, it doesn’t follow the structure of a computer science IF statement. Here are a few lines:

If you can keep your head when all about you
  Are losing theirs and blaming it on you,
If you can trust yourself when all men doubt you,
  But make allowance for their doubting too;
...

In programs, an IF statement has a specific structure. It consists of a test of something that is true or false but then gives a specific action to take when the statement is true. The lines

you can keep your head when all about you are losing theirs AND blaming it on you,

is more or less such a true or false statement. Either you can keep your head or you can’t. This though ignores the possibility of you sometimes losing your head and sometimes not. The poem presumably means to say that you must ALWAYS keep your head. What exactly does “when” here mean too? The reason we do not use English when writing programs is the lack of clarity of what is actually meant. Programs are mathematically precise in their meaning. They do only have one possible meaning (and that is the point). this is also a potential issue of writing programs by instructing AIs over what you want in English!

This boolean expression (something that evaluates to true or false) also uses a logical connective AND just like in a program – you must both be keeping your head AND people must be blaming it on you for the whole to be true. If they are both true then the action that follows is taken, but if they aren’t both true the poem says nothing about you!

Another issue in If, is that this test / boolean expression is not immediately followed by an action to do when it is true. The action comes right at the very end of the poem

...
Yours is the Earth and everything that's in it,
And - which is more - you'll be a Man, my son!

This comes after a whole series of these partial IF statements. To make it more clearly like a program you would add a more explicitly IF-THEN structure, which is the equivalent of putting ANDs between all the tests. In a program that would be written more like the following:

IF you can keep your head when all about you
  Are losing theirs and blaming it on you,
   THEN IF you can trust yourself when all men doubt you,
              But make allowance for their doubting too;
...
...
                             THEN Yours is the Earth and everything that's in it,
                                        And - which is more - you'll be a Man, my son!

Only if all the tests are true does the final action get taken. Though it isn’t really an action, it is more an assertion that something else is true – “the Earth is yours”, rather than “we give you the Earth”. (Also that final And is no longer a logical connective!)

Poems like this could be made more explicitly computational though. For example, a slightly more computational version might be:

IF you can keep your head when all about you
   Are losing theirs AND blaming it on you
THEN I will thank you, giving you a pay rise too
...

A love poem in this vein might start

IF you are a snail 
    THEN I will become your shell.
IF you are a ...

This leads on to the idea of pseudocode poems, that use other computational constructs. More of that to come.

To do …

  • Write your own poem in this style with true/false questions followed by specific actions, modelled on the computational version of IF. It could be a reworking of If itself or a completely different poem.

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Great Fleas… a poem about recursion

A flea
Image by Doğan Alpaslan Demir from Pixabay

Computer scientists and mathematicians can be poets too, even writing poems about computation. One of my favourite poems is about recursion and was written by the Victorian logician Augustus De Morgan who is famous for his laws of boolean logic that are a mainstay of reasoning about boolean tests in programs.

Great fleas Have Lesser Fleas,
upon Their backs To Bite’em,
And Lesser Fleas Have Lesser fleas,
And So, Ad infinitum.


and Those great Fleas, Themselves, In turn
Have Greater Fleas To go On;
while Those Again have Greater still,
And greater Still, And So on.

– Augustus De Morgan

Recursion, solving problems by breaking them into smaller versions of the same problem, is a way of writing programs that repeat just using function call (no while loops or for loops needed). It is a core concept of the programming paradigm, functional programming. Using recursion in a way that goes on forever as in the poem leads to non-terminating programs.

De Morgan was also Maths tutor of Victorian mathematician and computer scientist, Ada Lovelace. Her father was the great poet Lord Byron though (philistine that I presumably am) I like De Morgan’s poem better than Byron’s.

De Morgan made the idea of mathematical induction rigorous. It is the basis of how you prove recursive programs (and iterative ones) are correct.

Paul Curzon, Queen Mary University of London

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Lego Computer Science: Programming Creativity

White lego buildings rising from rubble
Image by Paul Curzon taken at Tate Modern London at Olafur Eliasson’s “The cubic structural evolution project” exhibition, 2019.

My absolute favourite example of interactive art is Olafur Eliasson‘s “The cubic structural evolution project” back in 2019 at Tate Modern. It was “just” two piles of standard white Lego bricks piled on two tables (but a tonne of Lego between the two …so a LOT of Lego). Anyone visiting the exhibit was invited to sit down and help create a city by building a building … and it was joyfully creative. Kids and adults mixed together building great architectural wonders, big and small, out of the bricks. Sometimes intentionally, but often accidentally, an existing building was demolished, but that was just an opportunity for new amazing buildings to emerge from the rubble. We visited twice that summer, and each time a totally different city was there that had emerged from this constant evolution of building. On each visit we built something new ourselves to add to the ever changing city.

The exhibit took Lego back to its roots – no instructions, no specific creation to reproduce, just the bare building blocks of creativity. You can still buy generic lego sets of course (if not with the same scope as a tonne of bricks). However, the high profile modern Lego sets are now used to build a specific thing designed by someone else, like a Star Wars Tie fighter, a Death Star, a Ferrari, a parrot or perhaps Notre Dame. This is one form of creativity – you are definitely creating something, and doing so gives you an amazing feeling of accomplishment and well-being. I strongly recommend it and of doing similar activities whether doing a tapestry, or building a jigsaw, or … It is good for your happiness and mental health more generally. But you are creating just by following instructions. In computer science terms, you are acting as a computational agent, following an algorithm that if followed precisely guarantees the same result every time (an exact copy of the lighthouse on the box perhaps…). A computer (with a suitably good robotic arm and vision system) could do it. That is the point of algorithms! They take no thought just an ability to follow instructions precisely: the thing computers are good at.

There is another sense we mean when we talk about creativity though and that was the original Lego idea. You have the bricks. You can build anything. It is down to you. Create something new! According to an exhibition on the history of play I went to early construction kits like the original Lego inspired a whole generation of architects to do completely new things with buildings (if you know your architecture think especially Frank Lloyd Wright whose mother bought him educational blocks called the Froebel Gifts, or perhaps Denys Lasdun – I lived in one of his “Lasdun building” block like buildings for a year in my younger days).

This kind of pure creativity is what being a programmer is about. Not just following instructions to create someone else’s creation, but creating your own totally novel, wondrous things from simple building blocks (and you don’t have to be part of the Lego design team to do it either). That is the lesson that collaboratively emerged in Olafur Eliasson’s exhibit over and over again. Just as the inventor of Lego, Ole Kirk Christiansen, in creating the toy went to yet another level of creativity in doing so, Olafur Eliasson did so to in creating the exhibition. They both created the opportunities for others to be creative.

Programming languages are very much like Lego in this sense. They just provide the building blocks to create any program you want. Learn how to use them and you you can do anything if you have the imagination as well as having built the skill. The different constructs are like different kinds of Lego bricks. Put them together in different ways and you create different things. You can stick with the basics and still build amazing creations even without learning about all the libraries methods that act like specialist bricks designed for specialist purposes. And of course the early Computer Scientists who invented the idea of programming languages were being creative in the way Ole Kirk Christiansen and Olafur Eliasson were, creating the possibility for others. Creating possibilities for you.

The Arts are about pure creativity but so is Computer Science…(and when they are brought together by creative people even more amazing things can be created (by everyone).

Paul Curzon, Queen Mary University of London

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The Knights Templar Cipher

The Knights Templar flag. A red cross on a black (above) and white (below (background)
The flag of the Knight’s Templar. Image by CS4FN

The Knights Templar were a 12th century order of catholic warrior monks, more accurately if convolutedly called “The Poor Fellow-Soldiers of Christ and of the Temple of Solomon” though they weren’t exactly poor. In addition to their original role of protecting catholic pilgrims heading to Jerusalem from robbery and murder, they also acted as a kind of international banker to support their main role. They laid some important foundations of modern international banking in the process. In particular, they invented a way to move money (or gold) around safely, without ever actually moving it anywhere. That sounds like a magic trick! Did they use some supposed mystical magic powers to do this? No, they kept the actual money given to them in the nearest of their large network of 1000 or so headquarters and forts around the continent. The money didn’t have to move anywhere. They then gave the person a note to hand in at their headquarters in another country. It promised that the Knights there would give them the equivalent amount from their money store when asked and given the note. The Knights there just swapped them the money for that note. This worked as long as they had a suitable store of money in each location, which of course would be topped up each time someone wanted to move money from that point. This is a simple version of how international banking works now. A British 20 pound note just promises to pay the bearer an equivalent amount, and without that promise (and people’s belief in it) it is just a piece of paper. It is just a similar promissory note, except people now just swap notes, treating it as money in its own right. Similarly, the banks don’t actually move any gold or other physical form of money about when you pay a shop with your debit card or banking app. They just move information equivalent to those promissory notes embodied in the transaction, around a network (though a computer one rather than a network of forts connected by roads).

There is a problem though with moving money from one person to another in this way using notes. If someone steals the note then it is potentially as valuable to them as actually stealing the chest of gold left in the original fort (just as stealing a 20 pound note is). In the Templar’s time the thief would just need to take it to a Templar headquarters and swap it for money just as the original owner would have done (a bit risky perhaps, given how fearsome the Templars were, but potentially possible!). Worse though, without a system to protect from this kind of attack, a thief could copy the note and then ask for the money repeatedly!

However, the Templars are know to have used encryption in their communications. The notes may therefore have been encrypted too and if so that would have made them useless if stolen. Banks now encrypt all those messages that move money about computer networks for the same reason. If only the Templar’s could read their notes (as only the Templar’s knew the key to their code), then only they could know it even was promising money. That doesn’t fully make it secure though, perhaps a thief could guess it was such a note, and if so what is to stop them then trying to cash it in (apart from the risk of being wrong). You would need something more. A simple possibility is the person with the note would need to know the encrypted amount that was contained somewhere within it. If they didn’t ask for the right amount then they couldn’t have handed over the money in the first place. They would reveal themselves as a thief!

Modern banks have to deal with similar problems even though modern financial transactions are all encrypted. Simple encryption alone is still not enough, protocols (special algorithms) are needed to prevent wide ranging kinds of attack being possible. Banks also need to use better ciphers than those from the Middle Ages, as today we can quickly crack ciphers as simple as the Templar Cipher. Banking is all done differently in detail today, but the ideas behind what is done and why are the same.

Can you crack the Templars’ cipher and decrypt the message below? One way might be using frequency analysis. The most common letters in English are likely (if not definitely) the most common in the message. E is most frequent in English, so which symbol might stand for E? Frequency analysis had been known for several hundred years before the Templars used ciphers (at least by the Arabs, though the Templars weren’t exactly their friends!), so it is actually possible even then that the Templars’ messages might be cracked, unknown to them. It was an Arabian scholar called Al Kindi, who actually invented frequency analysis (or at least was the earliest known person to write about it in his manuscript “On Deciphering Cryptographic Messages”.) Another way to crack the code might be to look for cribs – what words might be included in the message if it is a promissory note? Using both together may give you a good chance of decrypting the message. If you can’t crack their code (there is a big clue in this article), the key is given at the end if you scroll down. Use it to then decrypt the message.

Templar Cipher Puzzle using triangles, diamonds and other symbols.

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This blog is funded by EPSRC on research agreement EP/W033615/1.

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Scroll down for the solutions

Solutions: The Key

The Templar’s cipher uses symbols based on their flag’s triangles. To encrypt a message swap letters for symbols. (They had no J).

The cipher mapping symbols to letters§§

Can you decrypt the message given the above key? Here is an example – the message HELLO as encrypted in this cipher.

HELLO in the cipher

Scroll down further for what the message says…

Solutions: The Message

The message reads …

GIVE KING PHILIP OF FRANCE ONE HUNDRED GOLD PIECES