This intuitive design can help you create a stove out of just a few cinder blocks and some kindling. The "four-block rocket stove" is a design that utilizes three standard cinder blocks and one notched cinder block that kind of looks like an I-beam. By lining the I-beam block up with the opening you're feeding kindling, fire will be able to rise up through the top block and heat the pan sitting on top so you can make yourself a meal!
This is a great hack if you're homesteading or doing some off-grid construction. You and your fellow workers can huddle up around the stove and take a nice, cinder block-cooked lunch break.