No 2. Liquid heater
Used to probably heat tea or coffee or whatever, this immersion heater is made from razor blades and an electric cord giving you an idea of inventiveness and creativity of the inmates.
No 1. Stove
Made by a prisoner in Germany using a broken heater, aluminum foil and some wire, this heater is a good invention for those prisons where use of hot plates is not allowed. What’s better than cooking your own food?