Algebra-cadabra! Here’s a classic magic trick, and the mathematical secret behind it..
Here’s thanking Alex in Numberland and the Guardian for this brilliant bit of MathMagic.. I’ve performed this effect a number of times and it never fails to amaze…
You only need a cursory familiarity with the work of magicians like Derren Brown and David Blaine to realise that at the heart of many illusions lies a piece of rock-solid mathematics.
Sometimes tricks require fooling people with probability, as Brown expertly did in The System, his classic show about predicting the results of horse races.
And sometimes it relies on genuinely surprising and clever theory.
The literature on mathematical magic overwhelmingly concerns tricks using playing cards.
Irishman Colm Mulcahy is a legendary cardsmith in the mathe-magical community, and his lovely new book Mathematical Card Magic is jammed with entertaining and thought-provoking tricks.
Here’s one that’s in the book…