Black 2x4x6 Fully Functional Cuboid by Calvin's Puzzle Difficulty: Hard, for advance cuboid solver Fully Functional Cuboid, shape shift Use the same mechanism as the 4x4x6, it's basically a shave down version of it Not for speed cube, can pop if the cube isn't aligned while you turn Some bubble on the stickers because of the curve surface, you may need to glue it down