X-Ceter-O is a new twist on the classic Tic-Tac-Toe game. It includes six game pieces: three Os marked 1, 3 and 5 and three Xs marked 2, 4 and 6. You play on 3 x 3 game board grid. The pieces are played in numerical order. Once the six pieces are on the board, play continues in sequential fashion, with each move exposing the now-vacated square to the opponent. The action ends only when the first player achieves a three-in-a-row combination. With this game there is never a tie. - BoardGameGeek