While it seems commonplace now, the Fresnel lens was an important ... a lighthouse was an oil lamp, a concave mirror, and an ordinary lens. This made the lighthouses difficult to spot.

Warner learned through a process of trial and error, trying different concave and Fresnel lenses plus a tiny square mirror he found at a craft store. Once he found the combination that worked best ...

Fresnel lenses are all around us, but this vase puts the commonplace technology to work in an entirely new way. Borrowed From Old Lighthouses, A Method For Super-Powerful Solar Power With the help ...