The sculpture was two sides of the same polished rocks that bordered both sides of the path leading from Moscone Center to the Children's Area. They appeared to reflect onto the path. But notice that the left hand one was shaded so could not reflect.

The horizon was painted onto the polished surface. Its reflection was painted on the surface of the path.

The painted horizon on the other side was actually lit by the sun, but it too had its surface painted and the reflection on the ground was also painted.

A closer view of one of the double horizon art pieces, revealed a semi-transparent plastic overlay applied to each polished surface.

The sign identifying this art was mounted on the dirt to one side of the sculpture. It both identifies the art and artist, but also explains the artist's reason for creating this art in the first place.