Creation of this applet was inspired by a [url=http://gogeometry.com/school-college/2/p1145-three-squares-midpoint-math-problem-solving.htm]problem[/url] posted by [url=https://twitter.com/gogeometry]Antonio Gutierrez[/url] (GoGeometry). [br][br]You can move the [b]4 LARGE POINTS[/b] anywhere you'd like [b]AT ANY TIME[/b]. [br][b][color=#0000ff][br]How can we formally prove what is dynamically illustrated here?[/color][/b]