We are all makers
Uwe Oehler has written a simple program that prints out fold-up paper templates for the conic sections that make up the reflective surface of a Fresnel mirror. Cut the templates out of cardboard, cover the cardboard with aluminum tape, fold up the sections, and apply them to a flat backing. Even the relatively simple, five ring, 59% coverage reflector shown in the video will burn holes in construction paper under modest sunlight. [via Hack a Day]