JDB Games' Vertical Gaming System are a series of 3D Tic-Tac-Toe games that help prepare students to understand and enjoy the fantastic Time Vectors.3x3x3 Tic Tac Toe: Play until a student can always win if (s)he goes first. 4x4x4 Tic Tac Toe: Like Qubic, the first player can always win, but the solution isn't readily apparent. 5x5x5 Tic Tac Toe: An even further expansion, it's also possible to play for four-in-a row on this matrix.Remember, these systems are stepping stones to Time Vectors--a wonderful, educational game for improving visual-spatial awareness. - BoardGameGeek