  Two triangles are called orthologic if the perpendiculars from the vertices
of one of them to the sides of the other are concurrent. In this paper, we
explore the concept of orthology from various points of view. Mostly we work in
terms of elementary geometry in $\mathbb{R}^2$. In the final section, we relate
the discussed concepts to $\mathbb{R}^4$. A key idea in this paper is that two
orthologic triangles generate a one-parameter (linear) family in which any two
triangles are orthologic. Working with such a family can provide a natural
approach to certain questions.
