The Umbilic Torus
Helaman Ferguson's The Umbilic Torus is a single-edged three-dimensional figure created as a mathematical artwork. It adorns the Kalmanovitz Library of UCSF, Parnassus Avenue. The lone edge goes three times around the ring before returning to the starting point. A cross-section of the surface taken from an umbilic torus corresponds with a hypocycloid. Students love the mind-boggling feeling that the artwork brings.