Let A'B'C' be the cevian triangle
of a point P. Let Oa, Ob, Oc be the circumcenters of PB'C', PC'A', PA'B'.
The triangles ABC and OaObOc are orthologic, with an orthologic center
P and the other a point Q.
When P is the centroid, Q is the ninecenter.
When P is the Steiner point, Q is the
De Longchamps point
