An AI that plays Tic Tac Toe.

Notes: Instead of X's, O's, and Blanks, we use True, False, and None. True is you, False is the ai, and None is blank.

mark1: Computer plays random (uniformly) valid moves. Human plays first.

mark2: Computer plays random (uniformly) valid moves, but will not make the same mistake twice. First player is decided randomly (uniform).