Creation of this resource was inspired by a [url=http://www.gogeometry.com/ArchBooLem03.htm]problem[/url] posted by [url=https://twitter.com/gogeometry]Antonio Gutierrez[/url] (GoGeometry). [br][br]You can move the ANY LARGE POINT anywhere you'd like.[br][br][color=#0000ff][b]How can we formally prove what is dynamically illustrated here? [/b][/color]