Tic Tac Toe Like

A logic game between two opponents on a 3 by 3 square field. One of the players plays "crosses", the second (computer) - "noughts".
The players take turns putting 3x3 signs on the empty cells of the field (one is always crosses, the other is always zeroes). The first player to line up his 3 pieces vertically, horizontally or diagonally wins. The first move is made by the player placing crosses.