The visitor puts a metal ball (planet) in the track and follows what happens in the mirror above. By seeing the ball rotate, around the center hole in a black painted funnel, from a distance, it appears to be a 2-dimesional event. Just like a planet is captured by a black hole in space. A blue light on the black walls inside supports the impression of space environment.

To give the visitor a clue of how it works there are 2 glass provided vertical slots (not seen on the picture). 

Maintenance: No
Material: Plywood, glass, glass fiber
Colour: Black
Diameter: 900 mm
Height: approx 3000 mm