Tic-tac-toe also known as the X's and O's. It is originally idea from a pencil and paper game for two players.

User is challenging the computer. O and X represent each of the player, who take turns marking the spaces in a 3 x 3 grid, usually X going first. The player who succeeds in placing three respective marks in a horizontal, vertical or diagonal row wins the game. Credits: webiness.com