I've heard of the double cube - do you have any idea where to buy one?
Another strange cube I've seen, is a normal 3x3x3 with extra cubies glued on
three faces so that it looks like a 4x4x4; of course, it twists in a very
lopsided manner. The main problem in making one (which I have not solved)
is how to grind or cut the flanges off cubies before gluing. Without
equipment, can anyone think of a good, practical way to do this?