Principles And Construction 4:
Wall Shape

The rooms of the Potters' house are shaped like the letter U. Their arched backs face away from the sun; sheltering earth berms cover them.

The U shape has two functions: it serves as a 'pocket' to capture heat, and the curve of the U acts as an arch to help withstand the weight of the earth piled up on the back of the house. The rest of the walls serve as buttresses to support the ends of the arch against the earth.

The Daniel Johnson dam in Quebec uses the same principle.

Next: how the thickness of the walls serves several functions.