Erratic Grass is a kinetic sound sculpture consisting of 150 aluminum rods with stones affixed to their ends. Visually, the piece references the form of ornamental grasses.
The stones, which were sourced from the area surrounding where the piece is situated, are erratics, left behind when the glaciers retreated.
The stones vary in type, shape, and weight, with heavier stones causing the rods on which they are mounted to bend further down.
When the rods are disturbed by natural forces (such as wind) or by the hands of visitors, they are set into motion, producing sound as the rods and stones contact and rub against one another.
The term "erratic" in the piece's title refers to both the nature of the movement of the piece as well as the stones used in its creation.