Right Triangles Set Up - (Nothing much happens yet - code missing) Click the Flag to start Change the Short (a) & Medium (b) sliders to change Triangle drawn. Hit the (Proof) button to see an animation of Pythagoras' most elegant proof by re-arrangement of the Theorem bearing his name. Hit Space to switch back to drawing right-angled triangles. When the missing code is written it will draw Right-Angled Triangles and show the proof by re-arrangement of Pythagoras' Theorem.