On one ordinary day back in 2012, a hefty envelope turned up in my snail mail containing a very kind letter along with a mechanical drawing so detailed it made me want to chew my hair. The sender ...

Every Boy Scout or Girl Guide probably had the experience of building a simple solar oven: an insulated box, some aluminum foil, and plastic wrap, and voila! On warm, sunny, summer days, you can bake.

I can use my Sun Oven as a regular oven by refocusing it every 30 minutes to stay in alignment with the sun, or as a slow cooker by just leaving it alone to cook all day. Even after the sun goes away, ...