German-born painter, poet, sculptor and teacher. He is considered as one of the most influential art teachers of the 20th century, in part for his contribution to Color Field painting and Op art. He left Nazi Germany for the United States In 1933 and taught at Black Mountain College in North Carolina until 1949 before beginning a 10-year tenure as chairman of the art department of Yale University. He counted among his students Eva Hesse, Robert Rauschenberg and Kenneth Noland. His best-known series of paintings, Homage to the Square, begun in 1950 and continued until his death. These works consists of colored squares superimposed onto each other. Their arrangement is carefully calculated so that the color of each square optically alters the sizes, hues and spatial relationships of the others. These works were exhibited worldwide and formed the basis of the first solo exhibition given to a living artist at the New York City Metropolitan Museum of Art in 1971.