…man has yearned to barbecue with the sun.
In grade something or other — 5, maybe? — I did a science project about solar power. As part of this, I (with parental aid) built a solar hot dog cooker in a shoebox: essentially, a semicylinder of aluminium foil with a little skewer through the axis that you could turn. I don’t remember whether the device was ever tested for cook-worthiness.
Anyhow, this seems to be the same thing on a much grander scale. Also, Swiss.