Geared 5x5x5 is a higher-order variation to the Gear Cube. A set of gears make an inner layer turn at half the speed of an outer layer. This way, the outer layers can only be turned by 180 degrees. The gearing ration is 4:40, so the puzzle always retains it cubic shape, and the edge gears can only be flipped by 180 degrees. Still, the puzzle is fiendishly difficult.