Harvard Graduate Center, consisting of seven dormitories and a dining hall, gives form to the theories of Walter Gropius, who began teaching at Harvard in 1937. Gropius had directed the Bauhaus in Germany, where he promoted a cooperative approach between architects and designers. In Cambridge in 1945, he formed TAC, the firm that designed the Graduate Center. Organized into courtyards and linked by covered walkways, the buildings typify International Style architecture, with their boxy buff brick shapes, flat roofs, bands of windows that wrap the corners, and lack of ornament. In the spirit of Bauhaus cooperation, the architects commissioned artists to adorn the complex's central courtyard and interiors of the Commons building. Richard Lippold designed a sculpture, and Josef Albers, Joan Miró, and Jean Arp executed murals. Some of these were removed or covered during a renovation in 2004.