Claes Oldenburg and Coosje van Bruggen: Geometric Apple Core, 1991. Stainless steel, urethane foam, urethane shell, and latex paint. Doris and Donald Fisher Collection at the San Francisco Museum of Modern Art. © Claes Oldenburg and Coosje van Bruggen. Photo: © Ekevara Kitpowsong/Special to S.F. Examiner. © This artwork or photo may be protected by copyright. It is posted on the site in accordance with fair use principles.