“The Shape of Things: Photographs From Robert B. Menschel,” a survey of classic and provocative photography that covers 150 years of the art form, is on view at the Museum of Modern Art in New York through May 7. All of the photographs in the exhibit (by artists such as Aaron Siskind and Harry Callahan) were selected from the 500 works that have entered the Museum’s collection due to the support and generosity of Menschel, a trustee and former board chairman—many donated from his personal collection. PROVOKR members can sample some of the show’s iconic images, above and below.