Say hi to Teddy. He was sketched with a tool called, appropriately enough, Teddy (see http://www-ui.is.s.u-tokyo.ac.jp/~takeo/teddy/teddy.htm for starters). Teddy (the program) lets you turn freeform 2d sketches into volumetric 3d shapes instantly.

The results may be a bit primitive, but some would take that as a compliment. I know Teddy (the bear) would.