In “The Flatbed Picture Plane,” 1972, an essay discussing the work of Robert Rauschenberg, Andy Warhol, and others, Leo Steinberg posed the idea of a “tilt” in the conventional pictorial surface from vertical to horizontal. He argued that Rauschenberg’s scatterings of mass-media images and Warhol’s pictures of pictures demanded a perceptual reorientation, away from a “worldspace” (a view corresponding to a window on the world or the upright posture of the human form) and toward a “receptor surface,” such as a tabletop, the studio floor, or the flatbed printing press. According to Steinberg, the