3D tic-tac-toe

3D tic-tac-toe is an abstract strategy board game for two players that extends the classic pencil and paper game of tic tac toe into three dimensions, most commonly played on a four by four by four cubical array of sixty four cells, though a smaller three by three by three version also exists. Players alternate placing their own marker in an empty cell, and the first to achieve four of their own markers in a row wins, where the winning row can be horizontal, vertical or diagonal on a single board as in regular tic tac toe, or vertically in a column, or a diagonal line through four boards. Also known by the trade name Qubic and marketed by Parker Brothers, the game can be played with commercial board sets or simply with pencil and paper, and its extra dimension multiplies the number of possible winning lines far beyond those available in ordinary two dimensional tic tac toe.