Pythagoras Theorem by Rearrangement

One of my friends emailed me this GIF of the Pythagoras Theorem as derived by a geometric rearrangement.  We all know that a² + b² = c² but it is fascinating to watch it illustrated.

pythagoras theorem rearrangement

And, from my friend James T: "Archimedes, Pascal, and Newton are playing hide-and-seek. Archimedes covers his eyes and starts counting. Pascal looks around and hides behind a bush. Newton grabs a stick and scrapes a one meter by one meter square in the dirt and stands in it. Otherwise, he does not hide at all. Archimedes opens his eyes and looks around. Of course, he immediately sees Newton and calls, “I see Newton!” Newton calmly says, 'but hang on, one Newton in a square meter is a Pascal!'"