Electrical engineer Arvind Gupta has been making toys for the last 30 years - toys made from local trash that he uses to teach science to school children in the villages of India. Toys that the children themselves can make. Pieces of bicycle tubing and small sticks are used to make shapes that not only teach geometry, but construction principles. Add a few marbles, and he can teach you chemistry by simulating molecules. See what else Arvind Gupta can make from used film canisters, straws and discarded pieces of paper.