“[H]ow does that work? First rule, a good foundation that keeps the wall dry from the ground, and second rule, a good {{w|roof}} that protects from the top. The third rule, {{w|erosion}} control. Mud walls need speed breakers... so that the rainwater cannot run down the wall fast... [T]hese speed breakers can be lines of bamboo, or stones, or {{w|straw}} mixed into the mud. Just like a hill needs trees or rocks in order to prevent erosion, it works just the same way.”