The shadow of a rotating, suspended object is cast twice onto a wall, appearing within two circular projections, one yellow and one purple. A projector shines a focused, circular beam of light through an angled pane of yellow colour-effect filter glass and onto a mirror behind it; the beam reflects off both the filter glass and the mirror, creating two separate projections on the opposite wall. Because of the properties of the filter glass, the light reflected off of the glass’s surface appears as a purple circle, while the reflection from the mirror appears as a yellow circle, to the right of and slightly larger than its purple partner.

Both circular reflections are interrupted by a rotating, bent steel loop that hangs in their paths, producing a constantly morphing shadow in the centre of each projection. Because the angles of the two projections differ, the two shadows vary slightly. As the shadows rotate, the viewer’s eye interprets the shadow in the yellow circle to be lagging just behind its partner shadow in the purple circle, although the same loop casts both shadows.