It's not one giant semi circle. Lets say each semi-circle has a radius of about 2 ft (judging by the pictures). Every 8 ft section (1 wave/one full cicle) takes

It's not one giant semi circle. Lets say each semi-circle has a radius of about 2 ft (judging by the pictures). Every 8 ft section (1 wave/one full cicle) takes 2pi2 ~= 12.56, while the straight wall takes 8*2 = 16 bricks.