A squat candle is an improvised stove/lamp which is very simple and remarkably effective for cooking, lighting and heating.
To make one, first make an “X” or loose spiral of cardboard just slightly shorter than the height of a metal can. It's best to then drip molten wax all over the cardboard so that it gets partially absorbed and coats some of it. Then slide the cardboard into the can, and fill in the gaps with small pieces of wax. Once there's some wax in it, you can light the cardboard and aggressively “feed” the squat candle wax chunks until it gets a good reservoir in the bottom. When using it, it's good to feed it from time to time, but even unfed a decent squat candle will burn for hours.
I've had excellent experiences with these, and have used them to make coffee in the mornings and elaborate stews at night.
Be sure to extinguish them by putting something non-flammable and flat over the top – if they're not covered when they go out, they'll let off a lot of nasty smoke.