Grönlund-Nisunen Flow of Matter, 2012

A horizontal plane is set on a much smaller base. Narrow edges prevent tens of thousands of small steel balls from falling off the 140 x 140 cm surface of the horizontal section across which they keep moving. The light grey metal structure stands at about 35 cm above the floor and continuously tilts very slightly but steadily. The changing inclination would not be that noticeable, were it not for the movement of the balls. There are not enough of them to entirely cover the horizontal plane so that about a fifth of the mat grey surface underneath remains visible.