More often than not, normal games of tic tac toe end in a tie. However, in this version of the game, each player is only allowed to have up to 3 X's or O's at any placed at any given moment, meaning that the game continues until one of the players wins. When a fourth X or O is placed, that player's oldest piece is removed from the board. You can choose to play against another real person by taking turns moving, or play against the computer!