I played with fire a bit more after messing with the Sunlighter, this time using fresnel lenses.Ãâ If you are not familiar with a fresnel lens, picture a magnifying glass that is flat.Ãâ 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.Ãâ On a sunny day, it can light tinder in a matter of seconds.Ãâ The really large sizes can burn through a piece of wood, which is ridiculous and awesome at the same time.