Connect Four on 6 high, 7 wide grid, there are 4,531,985,219,092 positions for all game boards populated with 0 to 42 pieces. The game was first solved by James Dow Allen (October 1, 1988), and independently by Victor Allis (October 16, 1988). Allis describes a knowledge-based approach, with nine strategies, as a solution for Connect Four. Allen also describes winning strategies in his analysis of the game. At the time of the initial solutions for Connect Four, brute-force analysis was not deemed feasible given the game's complexity and the computer technology available at the time. Connect Four has since been solved with
Connect Four 2015 Winning Moves published Connect 4 Twist & Turn. This game variant features a game tower instead of the flat game grid. The tower has 5 rings that twist independently. Game play is similar to standard Connect 4 where players try to get 4 in a row of their own colored discs. However, with Twist & Turn, players have the choice to twist a ring after they have played a piece. It adds a subtle layer of strategy to game play. In 2018, Bay Tek Games released their second Connect 4 arcade game, Connect 4 Hoops. Players throw basketballs into