President Garfield's Proof
Move point A.
Slide the slider.
This work is motivated by Proof #5 at http://www.cut-the-knot.org/pythagoras/index.shtml#5.
You can read more about this proof at https://maa.org/press/periodicals/convergence/mathematical-treasure-james-a-garfields-proof-of-the-pythagorean-theorem