Here is a proof by dissection presented in an unconventional way. It appears that this proof was known in ancient times, both to the Chinese and the Greeks (see Eli Maor’s “The Pythagorean Theorem: A 4000-Year History”, pp 26 & 61). 11-14 year-olds can use the applet to explore the famous theorem, while 15-18 year-olds can try to figure out trickier questions about the loci of the vertices of the triangles.
