Pythagorus proof

What you see is:

1. A right angled triangle
2. Then a square appears on its hypotenuse
3. Then the triangle flips inside the square
4. Then three more identical triangles appear inside the square. The short sides line up with the long sides because the sum of the internal angles of a triangle add up to 180°
5. Then the top triangle swivels around to the left side
6. Then the right hand triangle swivels around to the bottom side
7. Now the original square (on the hypotenuse) has changed shape and becomes mustard colour
8. Then this new area is divided into two squares, the beige one is the square on the short side and the red one is the square on the long side
9. QED