Let H be the orthocenter; Ha, Hb, Hc its orthogonal projections on the perpendicular bisectors of the sides. Let Hab, Hac be the orthogonal projections of Ha on the B-bisector and the C-bisector, and define analogously Hbc, Hba, Hca, Hcb. The lines HabHac, HbcHba, HcaHcb and the Euler lines of HaHabHac, HbHbcHba, HcHcaHcb concur (six lines) at the same point.