Dumbbell Cube is a challenge for intellectual weight lifters. This puzzle has two Rubik's Cubes that are connected through an intricate gear system. If you turn a face on one cube, a face at the other cube will follow. However, the connections between the two cubes have no symmetry. This makes solving this puzzle extremely difficult. Let's say Rubik's Cube squared.
Please order a 3D-printed do-it-yourself puzzle kit from Shapeways at this page (check with Oskar about screws and stickers), or contact Oskar directly if you are interested in obtaining a fully colored, stickered and assembled sample of this puzzle.