Tic Tac Toe Plus is a version of the classic game for one or two players, for Mac OS X.
Tic Tac Toe Plus can play a standard game of Tic Tac Toe, or a variation inspired by Trilite, a game for Mac OS 9 by John Mauro.
In Plus mode, only each player's three most recent moves remain in play, i.e. when a player makes their fourth move, their first move is removed, and that square is cleared for possible selection by the opposing player. This method makes gameplay more interesting by removing the possibility of a stalemate.