In differential geometry, the term "cyclide" refers to a surface whose "lines of curvature" are circles. These surfaces have multiple concrete geometric descriptions related to groups of angle-preserving (or "conformal") transformations on Euclidean three-space. This image was created by mapping a product torus in the unit three-sphere (in Euclidean four-space) by "stereographic projection" to Euclidean three-space.
