r191	perspective, incenter, point X(79)
r192	incircle, ninecenter, radical center
r1253	orthocenter, Prasolov point, complement
r1254	centroid, symmedian point
r1896	centroid, ninecenter, concyclic points
r1897	centroid, altitude feet
r1898	centroid, altitude feet
r1899	orthocenter, altitude feet
r1900	orthocenter, altitude feet
r1904	excircles, altitude feet, point X(442), radical center
r1905	excenters, altitude feet, point X(80)
r1906	excircles, altitude feet, Spieker circle, tangent circles