What geometry theorem is dynamically being illustrated here?[br](Feel free to move any of the BIG POINTS wherever you'd like!)
[b]Thales' Theorem:[/b][br][br]If an [color=#1e84cc][b]inscribed angle[/b][/color] intercepts a [color=#1e84cc][b]semicircle[/b][/color], then that [color=#1e84cc][b]inscribed angle[/b][/color] is a [color=#1e84cc][b]right angle[/b][/color]. [br](Note how this is an immediate consequence of the [url=https://www.geogebra.org/m/ty3JP9wa]Inscribed Angle Theorem[/url]!)