  In a previous paper we have introduced the ortho-homological triangles, which
are triangles that are orthological and homological simultaneously.
  In this article we call attention to two remarkable ortho-homological
triangles (the given triangle and its first Brocard's triangle), and using the
Sondat's theorem relative to orthological triangles, we emphasize on four
important collinear points in the geometry of the triangle. Orthological /
homological / orthohomological triangles in the 2D-space are generalized to
orthological / homological / orthohomological polygons in 2D-space, and even
more to orthological / homological / orthohomological triangles, polygons, and
polyhedrons in 3D-space.
