Ultimate Tic-Tac-Toe

Based on the paper and pencil game of the same name.

Ultimate tic-tac-toe takes place on a 3x3 grid, with each grid cell containing a smaller game of tic-tac-toe. Players take turns making moves, with X going first. The first player can go in any of the 81 available spots. For all turns afterwards, a player can only play in the small tic-tac-toe game in the same relative position as the previously played in cell relative to its game.

For example, if X plays in the bottom-left corner of the right-middle game for his first turn. Then O on the next turn can only play in any one of the 9 spots in the bottom-left game. Say O plays right in the center of the bottom-left game, then X on the next turn can only play in any of the available spots in the center game.

Once a player gets 3-in-a-row on one of the small games, they win that game. If a player is sent to a game that is already won, or where all spots have been used up, then they are able to play in any spot in the entire game. The player to win 3 small games in a line is the winner. If all small games are won without an overall winner, the game is a tie.