Term applied to certain synthetic materials that can be moulded in various ways, including being used in sculpture. The earliest such use is credited to the British chemist Alexander Parkes (1813–90), who exhibited various small objects made of his invention ‘Parkesine’ in London in 1862 and Paris in 1867. He won prize medals but was unable to develop his invention commercially. The first person to make serious and sustained use of plastic in sculpture was probably Naum Gabo, who often used sheets of transparent celluloid, especially in his small models. Other Constructivists, including Moholy-Nagy, likewise used plastics, but it was not until after the Second World War that they became major additions to the sculptor's materials. Pop artists, for example, have often utilized plastic's sleek, glossy surfaces, and Superrealist sculptors have found fibreglass (plastic reinforced with glass) an ideal material for creating lifelike figures. It is strong but fairly light in weight; it can be cast in a mould, with a very smooth finish; and it can be naturalistically coloured.