The cover of the K. O. Friedrichs book From Pythagoras to Einstein
shown in the previous post suggests a review (click the Log24
images for webpages where they can be manipulated) ….
The "more sophisticated" link in the first image above
leads to a webpage by Alexander Bogomolny,
"Pythagoras' Theorem by Tessellation," that says
"This is a subtle and beautiful proof."
Bogomolny refers us to the Friedrichs book, from which one of
the illustrations of the proof by tessellation is as follows —
For a quite different use of superposition, see
The Lindbergh Manifesto (May 19, 2015).