Years ago, I remember reading one of Martin Gardner’s Mathematical Games columns (from March, 1962, in case you want to look it up) where he described an interesting machine for playing tic-tac-toe. It was made entirely out of matchboxes, each one of which had a tic tac toe position on the top. Inside was a collection of colored beads. Each color specified a possible legal move for the position on top. The idea was that you’d play a game by drawing these beads from the appropriate box, and making the appropriate move. At the end of the game, you’d remove the bead from the last box that sent you along the losing path. Eventually, all the losing moves get removed, and the machine plays perfect tic-tac-toe.