Let Aa, Ba, Ca the contact points between the A-excircle and the sides. Define analogously Ab, Bb, Cb, Ac, Bc, Cc. Let X = CbAbÇAcBc, and define analogously Y, Z. Let X' the projection of Aa on BaCa, and define analogously Y', Z'. The triangles XYZ, X'Y'Z' are perspective with center the orthocenter of XYZ.