Much of the story of twentieth-century art can be told as a series of acts of vandalism. Cubist collage attacked the expectation that a painting should look like something in the world. “In my case,” Picasso said, “a picture is a sum of destructions.” Abstract painters criticized Cubism for not going far enough: “Cézanne broke the fruit dish,” Robert Delaunay reportedly said, “and we should not glue it together again, as the Cubists do.” Marcel Duchamp, not satisfied with assaulting painting from within, abandoned the medium after 1918, turning his attention to the presentation of ready-made objects as art, the most infamous of which was the urinal, entitled Fountain, he submitted to the American Society of Independent Artists under the pseudonym “R. Mutt” for its inaugural exhibition, in 1917. Whatever else Duchamp’s gesture was — a provocative way of blurring the boundary between art and mundane objects, a critique of the idea of authorship — it was also a metaphoric micturition on the history of creative expression. Another work of Duchamp’s, L.H.O.O.Q., consisted of a cheap postcard-size reproduction of the Mona Lisa, on which he drew a mustache and goatee. Pronounced aloud in French, the title sounds like Elle a chaud au cul, which translates colloquially to something along the lines of “She’s horny.” Duchamp’s focus was on degradation, setting the stage for the deskilled and frequently scatological experiments of a range of progeny, from Dubuffet to Warhol to the Andres Serrano Piss Christ that so pissed off Jesse Helms.