A Pop-11 program demonstrating a proof of Pythagoras theorem [Please see note about verbal slip]
Channel: aaronsloman
Date: 30/03/2014

Pythagoras' theorem (which seems not to have been discovered by pythagoras, who lived long after it was already known) has been of great importance in the history of mathematics, science and engineering. It has been proved in many ways, which is an indication of its depth. This video shows a pop-11 program running, which shows one of the (many) proofs of the theorem, in the form of a video.

[NOTE ADDED 1st Nov 2015]
Unfortunately during the commentary I referred to the four equivalent triangles that had been created as four *squares*. I  hope that slip will not hamper anyone's understanding of the proof after this acknowledgement.
[END NOTE]

The pop11 code that produces the video is part of the free, open source, poplog system. The rc_pythagoras library is here:
http://www.cs.bham.ac.uk/research/projects/poplog/rclib/lib/rc_pythagoras.p
It makes use of the rclib 2-D graphical libary in pop-11.

The tutorial originally appeared here:
http://www.cs.bham.ac.uk/research/projects/cogaff/tutorials/pythagoras.html
(Based on an idea by Norman Foo)

This presentation was unscripted and has several rough edges. I may improve it later.

Aaron Sloman
http://www.cs.bham.ac.uk/~axs
University of Birmingham, UK