Gear Cube Cube. Three 3x3 cubes are very similar to the original: the Gear Cube Extreme, the Gear Cube Ultimate, and the Even Less Gears Cube. Gear Cube Extreme: Unlike the original Gear Cube with 12 total gears, the Gear Cube Extreme (also known as the Anisotropic Cube) has only eight gears. The top and bottom rows remain gear cogs, whereas the middle layer edge cogs have been removed. Taking away the middle layer cogs and replacing them with standard edges allows for different movement between rows. Due to the added straight edges, the cube can now make 90° turns on two
Prince Rupert's cube the hole through which a cube larger than the original one (up to side length formula_2) may pass. The parts of the unit cube that remain, after emptying this hole, form two triangular prisms and two irregular tetrahedra, connected by thin bridges at the four vertices of the square. Each prism has as its six vertices two adjacent vertices of the cube, and four points along the edges of the cube at distance 1/4 from these cube vertices. Each tetrahedron has as its four vertices one vertex of the cube, two points at distance 3/4 from it on two of