Bernard Gibert and Floor van Lamoen,
The parasix configuration and orthocorrespondence,

Forum Geometricorum, 3 (2003) 169--180.

We introduce the parasix configuration, which consists of two congruent triangles. The conditions of these triangles to be orthologic with ABC or a circumcevian triangle, to form a cyclic hexagon, to be equilateral or to be degenerate reveal a relation with orthocorrespondence, as defined in an earlier paper

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