Let P, Q be two points, QaQbQc the pedal triangle of Q. Take Pa = APÇQQa, Pb = BPÇQQb, Pc = CPÇQQc. Then ABC and PaPbPc are perspective with center P, and the perspective axis envelopes an inscribed parabola with directrix HQ (H orthocenter) and focus X the antipodal of the isogonal of the infinite point of HQ.