"Parallel lines have a common end point at an infinite distance."

“Richard Westfall, Gerard Desargues, The Galileo Project”

“He who shall wish to disentangle this proposition will easily be able to compose a volume.”

“I freely confess that I never had taste for study or research either in physics or geometry except in so far as they could serve as a means of arriving at some sort of knowledge of the proximate causes... for the good and convenience of life, in maintaining health, in the practice of some art,... having observed that a good part of the arts is based on geometry, among others that cutting of stone in architecture, that of sundials, that of perspective in particular.”

“When no point of a line is at a finite distance, the line itself is at an infinite distance.”