La = the bisector of angle A,
Lb = the bisector of angle B,
Lc = the bisector of angle C;
Ga = reflection of line AG about La,
Gb = reflection of line BG about Lb,
Gc = reflection of line CG about Lc.
The three lines Ga, Gb, Gc meet in the symmedian point, labeled K in the sketch. It is also known as the Lemoine point. For a particularly good discussion, see
Ross Honsberger, Episodes in Nineteenth and Twentieth Century Euclidean Geometry, Mathematical Association of America, Washington, D.C., 1995.
