n the daytime to block out the
             heat. Then over the years, Hay and a man named John Yellott constructed a 3- by
             3.7-m building using water basins as the actual roofing material. During the
             summer, a slab of foam insulation was rolled back at night, and the water would
             become cold through the night sky evaporation. Since the water supply sat
             directly on a metal ceiling, it absorbed the heat from the room and kept the
             building air-conditioned all day. During the winter, t
             ...