Given a triangle ABC (see figure above), the
circumcenter O, Ninepoint center N, First F_{1} and Second F_{2} Fermat points
lie on a circle, called Lester circle.
This theorem was discovered by professor June A, Lester in 1996.
Reference: June A. Lester, "Triangles III: Complex triangle functions", Aequationes Mathematicae, volume 53, pages 4–35, 1997.
