Illuminated optical view of l’Hotel des Ambassadeurs In the Austrian city of Vienna (Wenen). The building is depicted in the distance, with an impressive baroque garden in the front. The outlines and light sources of the building are perforated (dots). At the back of the print we see that the holes are covered with see-through paper. Some of the holes are coated with green and red paint. This gives the illusion of coloured lights when the print is held in front of a light source.