The interactive figures on these web pages correspond to the figures in the paper "Mechanical arguments in geometry", written by Alfinio Flores, published in PRIMUS, 9(3), 241-250.

Abstract
Mechanical arguments are used to prove results in geometry. The use of concepts like velocity; composition, resultants, and equilibrium of forces; potential energy; center of gravity; and moment of force provide alternative and highly intuitive proofs.

• Click and drag on red points to move them.
• Click on buttons (when displayed) inside the sketch to cause objects to move, or new objects to appear and disappear. (If a button stays down when you click it, you can click a second time to release it.)
• When objects are animating or moving, press '>' to speed up motion or '<' to slow it down.
• Press 'r' on your keyboard to reset the sketch to its initial configuration.
• If the screen becomes cluttered with traced objects, click the red 'X' (when displayed) in the lower-right corner to clear the traces.