I played with fire a bit more after messing with the Sunlighter, this time using fresnel lenses. If you are not familiar with a fresnel lens, picture a magnifying glass that is flat. It uses grooved rings on the surface to focus light, and can focus the sun’s light on a single point if you aim it correctly. On a sunny day, it can light tinder in a matter of seconds. The really large sizes can burn through a piece of wood, which is ridiculous and awesome at the same time.