Hint: Try "unfolding" the walls, ceiling, and floor of the room into a flat "map" of the room: CAREFUL: It may not work . . . Why not? Do a better (more appropriate) map.
Try "unfolding" the walls, ceiling, and floor of the room into a flat "map" of the room:
CAREFUL: It may not work . . . Why not? Do a better (more appropriate) map.
