Let Ha, Hb, Hc be the altitude feet; ra, rb, rc the refelctions of the lines HbHc, HcHa, HaHb on the altitudes. Let A', B', C' be the orthogonal projections of A, B, C on ra, rb, rc. The lines HaA', HbB', HcC' concur at the midpoint between the orthocenter H and the point X(24).