Schloß Loburg, Ostbevern.

A circle is projected into a park-like garden from a second story window. A strip of grass and a half-circle of trees that form its boundary may act as a projection space. When a viewer enters a room next to the one with the projector and looks outside, the projected image will increasingly disintigrates the larger the distance between the viewer and projector is. As soon as he approaches the projector again the circle will be more perfect. But the perfect round is not conceiveable, because the ideal position is occupied by the projected slide.

Technical data: Slide projector, slide.