It’s been a while since I’ve made a post, today is an old Aztec way for making a right angle.
Most people don’t realize, but making a square base is pretty hard. Aztecs did it with a marked rope and 3 sticks. It’s based on the pythagorean theorem. A^2+B^2=C^2. You take a loop of rope that is 12′ long and mark a point. We’ll call this A. Any length will work, but to make this easier, we’re going to use 12 foot. Measure 3 feet from A and mark again. This will be B. Now, again measure 4 foot from B and mark as C.
Put a stake in the ground and loop the rope around it. Line the “B” mark . Stretch out the rope and put another stake at “A”, and then another at “C”. You now have a right triangle. The “B” angle is a perfect 90*. From this you can make perfectly square bases for all kinds of things.