Ultimate Tic-Tac-Toe is Mind Bending

By Norman Chan

A mathematician's game.

Ultimate Tic-tac-toe is a game math nerd Ben Orlin recently discovered at a mathematician's picnic. The game is played with one giant tic-tac-toe grid, with each of the nine squares filled with another smaller tic-tac-toe game board. The rules are a little more sophisticated than regular tic-tac-toe, though. The object is to win the big board by winning the right combinations of small boards, but each turn takes place in a different small board, which is determined by where your opponent last played. So players have to play a meta game of strategically placing X's and O's in the small boards to direct where their opponent will get to play next. Orlin says that when he plays it, strategies surface where players make intentionally bad moves in the small boards to avoid sending the other player into a good places in the larger grid. Yo dawg, it's tc-tac-toe Inception. (h/t Boingboing, Kottke, Andy Baio)