The circular shape of varicolored marble here is not for tensioning. It is simply that small segments of marble have been used rationally to make a circle. Large objects can be made from small stone elements which may thus result in a structurally homogeneous element called sculpture, unlike a house, let us say, which remains a piling of discrete stones. The structure of the sun translates into a visually powerful entity because of its inherent tensile unity of shape.