Scenes, objects, or imagery seen through a frame, screen, or other visible layer. This technique can often serve to frame, alter, or obscure one’s view, adding a sense of mystery or depth to a work of art. One of the most frequent ways artists achieve this effect is by depicting scenes seen through a window or from behind a screen. In the history of art, paintings of windows have often been used to symbolically demarcate inside and outside, public and private, background and foreground. Northern Renaissance, Impressionist, and Fauvist artists, such as Henri Matisse, frequently depicted scenes through windows to mediate and direct the viewer’s attention or to play with the idea of a painting as a “window onto the world,” a convention that has existed since the invention of one-point perspective. Perhaps the most famous example from art history is Marcel Duchamp’s Étant donnés (1946–66), an unsettling diorama of a female nude sprawled over a landscape. The sculpture itself is situated behind what appears to be a wooden door in a wall of the Philadelphia Museum of Art; the only way to see the scene is to look through a tiny slit in the door.