Gear Cube Black _ Meffert's Official Rotational Puzzle Black Gear Cube Extremely challenging rotational-sytle (Twist and Turn) Brain Teaser Puzzle. By twisting and turning the geared pieces on 3 different axis it is very easy to mix-up the puzzle. The object is to return each side of the cube to its original single color. The mechanism design of this puzzle makes it much more interesting than a standard rubik's cube. Smooth, easy rotation.