Convex & Concave, 1955

3 little houses stand near one another, each under a cross-vaulted roof. We have an exterior view of the left-hand house, an interior view of the right-hand one, and either an exterior or interior view of the one in the middle, according. Two boys are seen, each playing a flute. The one on the left is looking down through a window onto the roof of the middle house; if he were to climb out of the window he could stand on the roof. If he were to jump down in front of it he would land up one story lower, on the dark floor before the house. The right-hand flute player will find, if he climbs out his windows, that there is no floor for him to land on, only a fathomless abyss.