 Similarities exist in the semicircular temples found in the Temple of the Sun in Cusco, the Torreon in Machu Picchu, and the Temple of the Sun in Písac.In particular, all three exhibit a "parabolic enclosure wall" of the finest stonework, as Bingham describes it.Besides the structural similarities, there are similarities in usage, including the observation of solstices and Inca constellations.