Creation of this applet was inspired by a [url=https://twitter.com/CutTheKnotMath/status/894281828537962497]tweet[/url] from [url=https://twitter.com/CutTheKnotMath]Alexander Bogomolny[/url]. [br][br]Each [b][color=#666666]gray circle[/color][/b] is tangent to the [b][color=#bf9000]tan-colored circle.[/color][/b] [br]Feel free to move the [b]BIG WHITE POINTS[/b] and/or [b][color=#666666]BIG GRAY POINTS[/color][/b] anywhere you'd like. [br][br][b][color=#ff00ff]How would you describe the phenomena you see in words? [br][br]How can we formally prove what is informally illustrated here? [/color][/b]