Given three times, 2023–24
Two Tricks
Two magic tricks, one with a flipped bit and one with a deck of cards, and why they work
An introductory outreach talk, for a general audience.
Abstract
Draft, not yet checked by meTwo tricks, each hiding a computing idea. In the first, you pick any 16-bit string and any number from 0 to 15, and flipping a single bit is enough to make a fixed function of the string output your chosen number (it is the same mathematics as the famous impossible chessboard puzzle). In the second, a deck is cut any number of times, five people take the top five cards, and once those holding red cards stand up, every card can be named. I explain how both work, using XOR, binary encodings, and a deck ordered by a de Bruijn sequence.