(born Jan. 29, 1905, New York, N.Y., U.S. — died July 3, 1970, New York City) U.S. painter. Born to Polish immigrant parents, he studied at the Art Students League and City College. With Robert Motherwell and Mark Rothko, he cofounded the school called "Subject of the Artist" (1948), which held open sessions and lectures for other artists. He developed a style of mystical abstraction and achieved his breakthrough with Onement I (1948), in which a single stripe (or "zip") of orange vertically bisects a field of dark red. This austerely geometric style became his trademark and had a great influence on artists such as Ad Reinhardt and Frank Stella.