he began creating his constructions fashioned by combining disparate objects and materials into one constructed piece of sculpture; the sculptural equivalent of the collage in two-dimensional art. The advent of Surrealism led to things occasionally being described as "sculpture" that would not have been so previously, such as "involuntary sculpture" in several senses, including coulage. In later years Picasso became a prolific potter, leading, with interest in historic pottery from around the world, to a revival of ceramic art, with figures such as George E. Ohr and subsequently Peter Voulkos, Kenneth Price, and Robert Arneson. Marcel Duchamp originated the use of the "found object" (French: objet trouvé) or readymade with pieces such as Fountain (1917). Similarly, the work of Constantin Brâncuși at the beginning of the century paved the way for later abstract sculpture. In revolt against the naturalism of Rodin and his late-19th-century contemporaries, Brâncuși distilled subjects down to their essences as illustrated by the elegantly refined forms of his Bird in Space series (1924). Brâncuși's impact, with his vocabulary of reduction and abstraction, is seen throughout the 1930s and 1940s, and exemplified by artists such as Gaston Lachaise, Sir Jacob Epstein, Henry Moore, Alberto Giacometti, Joan Miró, Julio González, Pablo Serrano, Jacques Lipchitz and by the 1940s abstract sculpture was impacted and expanded by Alexander Calder, Len Lye, Jean Tinguely, and Frederick Kiesler who were pioneers of Kinetic art. Modernist sculptors largely missed out on the huge boom in public art resulting from the demand for war memorials for the two World Wars, but from the 1950s the public and commissioning bodies became more comfortable with Modernist sculpture and large public commissions both abstract and figurative became common. Picasso was commissioned to make a maquette for a huge -high public sculpture, the so-called Chicago Picasso (1967). His design was ambiguous and somewhat controversial, and what the figure represents is not clear; it could be a bird, a horse, a woman or a totally abstract shape. During the late 1950s and the 1960s abstract sculptors began experimenting with a wide array of new materials and different approaches to creating their work. Surrealist imagery, anthropomorphic abstraction, new materials and combinations of new energy sources and varied surfaces and objects became characteristic of much new modernist sculpture. Collaborative projects with landscape designers, architects, and landscape architects expanded the outdoor site and contextual integration. Artists such as Isamu Noguchi, David Smith, Alexander