Rocket stoves are fabulous! Easily built but capable of producing a hot flame that you can cook, I suppose, everything over. You can even bake bread with a little modification.
Knowing how to build one from bricks or stones is practical knowledge, that if held by people, such as those recovering from a disaster or Hurricane Katrina-like flooding, can help them get hot food prepared, without outside assistance, and get people fed.
Hunger is not a friend to humanity and knowing how to build and use a small rocket stove is a huge step toward self-sufficiency. Read the article below: