Any sculpture in which the figures project from a supporting background or flat surface. Reliefs are classified according to the height of the figures' projection or detachment from the background. In a low relief, or bas-relief (basso-relievo), the design projects only slightly. In a high relief, or alto-relievo, the forms project at least half or more of their natural circumference from the background. Middle relief, or mezzo-relievo, falls roughly between the high and low forms. A variation of relief carving, found almost exclusively in ancient Egyptian sculpture, is sunken relief (also called incised relief), in which the carving is sunk below the level of the surrounding surface and is contained within a sharply incised contour line. Intaglio, likewise, is a sunken relief but is carved as a negative image like a mold instead of a positive (projecting) form.