An array of unobtrusive, monochromatic posters is arranged along a segment of a passageway. Adjacent to the individual posters a distance sensor is watching when a pedestrian passes by the poster. The sensor is connected to a tele-objective camera flash and triggers it, casting the person's shadow momentarily on the poster. The poster's graphics being printed with fluorescent ink, captures the shadows making them an integrated element of the poster that gradually fade away.