There are many designs for efficient stoves, and gasification is only one way to boost the efficiency of a cooking fire. The wood gas stove in this article is an elegantly simple gasifier design called a TLUD stove (for top-lit updraft), also known as an inverted downdraft stove. If you don’t care how it looks, you can build it with a can opener, a punch, and a big rock. This design, which I’ve adapted from one I first saw on Instructables, is built around a 1-quart paint can. It easily boils enough water for a small pot of tea or a bowl of noodles, using nothing more than a fist-sized charge of scrap wood.