X(2), X(3), X(6), X(67), X(111), X(187), X(468), X(524), X(1560), X(2482), X(6593), X(10354), X(13608)
vertices of medial triangle
E = X(2482) = (b^2 + c^2 - 2a^2)^2 : : , complement of X(671), antipode of X(115) on the Steiner in-ellipse
K043 is the only circular pK with pivot G = X(2). Its pole is X(187), the Schoute center (inverse of K in the circumcircle).
The singular focus is X(14650), the midpoint of X(3)X(111).
K043 is :
More generally, given a circum-conic (C) with perspector W, the locus of point M such that the trilinear polar and the polar line in (C) of M are parallel is the pK with pole W and pivot G. It is the complement of the isotomic pK with pole W' = anticomplement of W.