GoGeometry Action 160!

Creation of this applet was inspired by a [url=https://twitter.com/gogeometry/status/1014313532127621121]tweet[/url] from [url=https://twitter.com/gogeometry]Antonio Gutierrez[/url] (GoGeometry). [br][br]You can move any [b]LARGE POINT[/b] anywhere you'd like [b]AT ANY TIME[/b]. [br][br][b][color=#0000ff]How can we formally prove what is dynamically illustrated here? [/color][/b]
Quick (Silent) Demo

Information: GoGeometry Action 160!