This cup belongs to a large group of early Islamic vessels that were decorated by pinching the surface with tongs. The metal tongs had circular or square ends containing the carved motif that was to be impressed in relief on the wall of the glass. Three different pairs of tongs, which produced triangular, circular, and heart-shaped patterns, were used to decorate the Corning cup. The makers of such objects may have been seeking ways to achieve some freedom of expression within the rules of repetition common in Islamic art. This freedom could be achieved by using different combinations of tongs, which bore patterns different from those of one- or two-part molds. Archeological finds indicate that this type of glass was traded extensively in the Islamic world during the ninth and 10th centuries.