Desargues Theorem (Spectrum Article)

This demonstrates Desargue's Theorem together with a Corollary as discussed in Mathematical Spectrum Volume 48, Number 3. The buttons make the points and lines needed fro the corollary visible/invisible.
Points P,A,B,C,A',B',C' can be moved - A',B',C' are restircted to the lines PA,PB,PC respectively.

Note that the line XYZ remains stationary when P is moved. This shows that it is dependent on ABC and the ratios l,m,n (from the article).

Camilla Jordan, 4 February 2016, Created with GeoGebra