Cook An Entire Meal With Just Twigs
A rocket stove is an efficient cooking stove using small diameter wood fuel which is burned in a simple high-temperature combustion chamber containing a vertical chimney and a secondary air supply, which ensures almost complete combustion prior to the flames reaching the cooking surface.
This could be the cleanest and most sustainable way to heat a conventional home. Some people have reported that they heat their home with nothing more than the dead branches that fall off the trees in their yard. And they burn so clean, that a lot of sneaky people are using them illegally, in cities, without detection.