r50	tangential triangle, extangential triangle, homothetic triangles, point X(55)
d	point X(33)
r141	tangential triangle, perspective, point X(56), incenter
r932	extouch triangle, perspective, cevian quotient, Nagel point, Mittenpunkt
r933	intouch triangle, perspective, incenter
r934	Euler line, circumcenter, incenter