Tic-tac-toe (also known as noughts and crosses or Xs and Os) is a 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 wins the game.
Players soon discover that best play from both parties leads to a draw. Hence, tic-tac-toe is most often played by young children.