This is a proof for the Pythagorean Theorem.
You can freely move the blue dots to change the size of the triangles.
the striped triangles are right triangles, legs length marked by a and b, hypotenuses' length marked by c .
according to the structure, Both squares size is (a+b)(a+b).
look carefully at the both squares, and match the right value from the value box on the bottom left to its right place.
after done, look at both squares and try to recreate equations that found from comparing both squares.