What geometry theorem is being dynamically illustrated in the applet below?[br](Feel free to move the BIG WHITE POINTS anywhere you'd like.)
[b]Theorem:[/b][br][br]If [color=#ff00ff][b]2 angles are supplements[/b][/color] of [color=#1e84cc][b]congruent angles[/b][/color] (or the same angle), then [color=#ff00ff][b]those 2 angles are congruent[/b][/color].