Tic-tac-toe (American English), noughts and crosses (Commonwealth English), or Xs and Os is a paper-and-pencil game for two players, X and O, who take turns marking the spaces in a 3×3 grid. The player who succeeds in placing three of their marks in a horizontal, vertical, or diagonal row is the winner.
In order to win the game, a player must place three of their marks in a horizontal, vertical, or diagonal row.
The following example game is won by the first player, X:
