A curve composed exclusively of circular Arcs.
See also Arc, Flower of Life, Lens, Reuleaux Polygon, Reuleaux Triangle, Salinon, Seed of Life, Triangle Arcs, Yin-Yang
References
Banchoff, T. and Giblin, P. ``On The Geometry Of Piecewise Circular Curves.'' Amer. Math. Monthly 101, 403-416, 1994.