Let A', B', C' and A”, B”, C” the cevian traces of the orthocenter H and the circumcenter O. Let Ahb, Ahc be the ninecenters of AA'B, AA'C and Aob, Aoc the ninecenters of AA”B, AA”C. The points Ahb, Ahc, Aob, Aoc are concyclic with center Oa. Define cyclically Ob, Oc (the figure shows only the construction of Oa). The triangles ABC, OaObOc are orthologic, with a center at the midpoint between H and the ninecenter N of ABC.