Thermocouple fan sitting on top of the New Scientist magazine. Today’s #bandofsketchers prompt was mechanical and this was the first thing that came to hand….. Heat from a fire is converted via a thermocouple into energy to rotate the fan. It should sit on top of something like a log burner so the base gets hot but hubby has it lying down in front of the halogen heater…. He likes watching it whirl…