Knowlton was known for her spherical sculptures, sometimes exhibited in groupings. In general, these were made from steel-reinforced concrete, and fiberglass. She also produced prints, photographs and drawings. Metropolitan Museum of Art, Union Art Center,
Pratt Institute,
San Francisco Museum of Modern Art, Dallas Museum of Modern Art, among many other venues. Her work received reviews in
the New York Times,
Architectural Digest,
Art in America, Sculpture Magazine,
Arts Magazine and
Vogue. The art critic,
Roberta Smith wrote that her work was "
Cubist in effect" and that it brought a "new complexity to Minimalist art". ==Collections==