3D5 by the Lolo Company is essentially a 3D Tic-Tac-Toe game played in a 5x5x5 cube, allowing 109 possible winning combinations. The one twist relative to a simple 5 in a row Tic-Tac-Toe game is that the center space of the cube is a "free" space, that can contribute to five in a row for either player. Optionally, players may specify up to nine additional free spaces beyond the center space as part of the set-up (game can with 10 neutral marbles). An interesting feature of this game is that it comes with a set of tweezers to manipulate the balls in the grid. The grid levels are only about 2 inches apart. Another odd feature is the posts that separate the layers. There are spacers between the layers with an elastic running through the center of the posts. Thus you can rotate the layers of the game and get it fold. There is a special peg provided to screw into the bottom tray holding the marbles to keep the game folded.