Foundations & Tilings in Perspective 
Foundations & Tilings in Perspective
by Richard Southwell
Video Lecture 3 of 16
Not yet rated
Views: 666
Date Added: March 5, 2015

Lecture Description

Protective geometry is more fundamental than euclidean geometry, with applications in physics, biology and perspective art. We shall introduce it visually, without equations.

This video begins by considering a hexagonal tiled hive from a bee's perspective. We then formally define projective geometry, discuss previous approach the study, like perspective art and geometry with only a straight-edge.

We discuss the famous hexagon theorem of Pappus. A foundation result of projective geometry. We also discuss the work of Descargues, and his brilliant idea about treating projective geometry as the study of constructions which can only be made using a straight-edge.

To contrast projective geometry with Euclidean geometry (which considers constructions using a straight edger `and' a compass), we compare how a hexagon is constructed in each geometry. In the projective case, we form the hexagon starting from three lines which pass through the vanishing line.

In the resulting projective construction of the hexagon we see many interesting qualities which are invariant of how the initial points are chosen. We point out how Pappus's theorem and Desgaurges' theorem can be seen working within this hexagon construction, and show how this construction can be extended to give a beautiful projective tiling of the plane with hexagons.

The Geogebra program can be found here:

I would like to thank Olive Whicher for his illuminating book on projective geometry, and Norman Wildberger for his insightful teachings on the subject.

My website is:

Course Index

Course Description

Protective geometry is deeper and more fundamental than standard euclidean geometry, and has many applications in fundamental physics, biology and perspective drawing. We shall introduce it visually, without relying upon equations. The hope is make this beautiful subject accessible to anybody, without requiring prior knowledge of mathematics. At the same time, there are some very deep, rarely discussed ideas in this subject which could also benefit experts.


There are no comments. Be the first to post one.
  Post comment as a guest user.
Click to login or register:
Your name:
Your email:
(will not appear)
Your comment:
(max. 1000 characters)
Are you human? (Sorry)