I have been coming across these 3-D puzzles and toys that are fascinating for kids and adults. Not only do they teach one to see in a non-linear manner, the craftmanship is amazing. I suppose 3-D computer modeling makes this kinda easy, still the idea is what is fascinating  One example is the D-Torso range from Aki Corporation, Japan, these “toys”, or one of them, was awarded the Good Design Award in 2001.