Beginning her career as a painter, the mixed-media artist Grace Knowlton became best known for her three-dimensional sphere sculptures, which she referred to as “paintings in the round.” Knowlton created spheres out of a diverse array of materials, including concrete, clay, copper, steel, and iron. The spheres, often varying widely in scale, all bear subtle and unique imperfections that evince their handcrafted origins. Knowlton initially set out to make ceramic pots, until, as she said, “I got so interested in closing the pots, in making a secret space closed off forever, that it caught me and I never went back.” Placed in the natural environment at Storm King, Knowlton’s Spheres walk a fine line between natural objects and works of art, and are often mistaken for actual boulders.