Rocket
I built a homemade rocket stove for my outdoor ritual area. You can find videos on how to make one on YouTube.
My variation has grooves for a couple of pieces of rebar to support the pot.
This thing works remarkably well.
I gave into the greenside on this one. There are also YouTube videos that show how to make fireplace fuel from wastepaper. I’ve been using my shredder for that. There’s a perverse pleasure in shredding your junk mail. Add a little water, some pressure, and some drying time and it turns into a serviceable fuel. It needs to be broken up to fit in the rocket stove though.