# The Geometry of Vision ## Lecture 5: Three Coincidences of Projective Geometry

Are there any interesting results in this geometry of points and lines?

In order to construct the harmonic conjugate, we freely chose points P and Q. Can we prove that the harmonic conjugate is truly independent of our choices?

Let's take a closer look at a second co-incidence, known as Pappus's Theorem!

And last but not least, let's examine Desargues's Theorem more closely!