Let three Isoscelizers, one for each side, be constructed on a Triangle such that the four
interior triangles they determine are congruent. Now parallel-displace these Isoscelizers until they
concur in a single point. This point is called the Yff center of congruence and has Triangle Center Function
See also Congruent Isoscelizers Point, Isoscelizer
Kimberling, C. ``Yff Center of Congruence.''