Three-Dimensional Tic-Tac-Toe is an expanded version of the classic game played on a 3x3x3 grid, creating a cube with 27 smaller cubes. Players take turns placing their markers, either X or O, in any of the 27 spaces. The goal is to connect three of their markers in a row, which can be achieved in various directions: horizontally, vertically, or diagonally across different layers of the cube. The game can be played by two players or against a computer. Winning requires strategic thinking, as players must anticipate their opponent's moves while planning their own. This version adds complexity and depth, making it a more challenging experience than traditional Tic-Tac-Toe.