Creation of this applet was inspired by a [url=https://twitter.com/gogeometry/status/840300539409752064]tweet[/url] from [url=https://twitter.com/gogeometry]Antonio Gutierrez[/url]. [br][br]Feel free to move any of the BIG POINTS anywhere you'd like. [br][br][color=#0000ff][b]How can you formally prove what this applet dynamically illustrates? [/b][/color]