The AI in this game is not predictable as in other games. Operation: Tic-tac-toe, also called OXO, Three in a line, noughts and crosses,Three in a row, X's and O's , is a pencil-and-paper game for two players, X and O, who take turns marking the spaces in a 3×3 grid. The X player goes first. The player who succeeds in placing three respective marks in a LINE horizontal, vertical, or diagonal row wins the game.