Computer Science Buskers? Step right up ladies and gentlemen.
It is I,Makita Yacov, the world’s greatest magician! Come, let me boggle and astonish your mind,
I will leave you flunnexed like a raspberry on a fence! You sir, yes you in the striped top, you look
like urban tiger, come, let me show you something.Are you really as good as you say you are?But of course I am! Would you expect any less
from a man who has cape and hat?I suppose not. So what can you do?Well, observe, I have here
a pack of multicoloured cards.They’re not multicoloured they’re just…
Silence, fool! Now, your task is to set these into a six by six square.
Do it, do it perfectly. Hurry boy hurry, I have not all day to prepare trick.
Come faster faster, move your digits. No! this is too easy,
allow me to add another row and column. Good! Now, while I face the opposite direction,
you take one of these cards and flip it over. Then, I turn around and reveal which card you flipped.All right turn around then.Done.This is your card!That was terrific!I know, because I am great!Incredible.So, how exactly did you do that?Excuse me? You think a magician as talented as I,
am going to give you my secrets.Ahh, come on I promise I won’t tell anyone.Yeah
WowThat’s very interesting.Yes, it is. But show or tell noone,
or there will be trouble! Do not mess with the great Makita Yacov!
[Laughter] Step right up step right up, I’m, uhh Trevor!
The greatest magician in all the world! Allow me to amaze you with my magic tricks!
You won’t believe your eyes. They’re so… Magic!Magic Trick eh?Yes! What I need you to do for me is
lay out these squares in six rows of six.SureFaster now, I don’t have all day, I am a magician
and I have other people to do magic for. Quick, quicker, quicker. All right that’s good,
and let me add another row just to make it a wee bit more difficult. Now, when I turn around, you will flip
one of the cards over. I’m turning around, and when I turn back,
I will tell you which card you FLIPPED. Oh. Ohh. What do you call this! I thought I told you
never to repeat my glorifying magic to anyone! Uhhh, I was teaching him how to play chess!
Yeah, chess. No what I meant to say was I was showing him
how computers store data using binary digits. Zeros and ones. See this square, it represents what is called a bit.A bit?Yeah, a bit, which is short for Binary Digit.
And sometimes these binary digits get flipped, and then the computer has to realise there’s an error
and work out which bit it needs to fix. I am furious, like pidgeon eating cricket bat!
I told you, never to mess with the great Makita Yacov! [Clapping] [Laughs] Now my collection is a littlebitbigger.
[Laughter] The secret of my trick is revealed at csunplugged.org
where it’s called Error Detection. But don’t go showing anyone, for if you do,
you too may be joining my fabulous team of bits. [Laughter]