Your uncertain shadow
Five coloured spotlights, directed at a white wall, are arranged in a line on the floor: a green light positioned next to another green light, followed by a magenta light, an orange light, and, finally, a blue light. These colours combine to illuminate the wall with a bright white light. When the visitor enters the space, her projected shadow, by blocking each coloured light from a slightly different angle, appears on the wall as an array of five differently coloured silhouettes.