Basically, you use a set of nesting clay pots, separated by and attached to a central steel bolt, with steel washers spaced in between the pots to form a heat exchanger thing. “Then you flip it over and support it on a few bricks to position the center bolt directly above a small candle or three. The flame heats the steel bolt directly, causing it to heat the clay pots and trap the hot air rising from the flame. The clay radiates heat. You’ll have to huddle close to it or use it in a small space, though. You can also use a couple of Sterno cans and a larger pot to get even more heat.”
