Arp, Jean or Hans (1887-1966), avant-garde French sculptor, painter, and poet, born September 16, 1887, in Strasbourg. Arp studied art in Weimar and Paris between 1905 and 1909 and then painted in Switzerland for several years. By 1912 he had become associated with Der Blaue Reiter (The Blue Rider), a group of Expressionist artists in Munich. Arp's work during the years 1915-1916 consisted of angularly patterned, totally abstract tapestries and drawings. In 1916 Arp helped found the revolutionary Dadaist school of artists in Zurich. In 1917 Arp's artistic style changed to the abstract, curvilinear forms that characterize his later work and for which he is best known today. In 1924 Arp moved to Paris, where he was associated with the Surrealists and produced painted wooden bas-reliefs and humorous cut-cardboard constructions. In the 1930s, Arp began to produce free-standing sculpture, carving and modelling in a variety of materials. An example of his smooth, biomorphic forms is Human Concretion (1935; cast stone version, 1949, Museum of Modern Art, New York). He also worked at various times in gouache, and made collages, engravings, and lithographs. Throughout his career, he wrote both poetry and essays. Arp was bilingual and called himself Jean when writing in French and Hans when writing in German.