Copy of Enlargement 3 Fractional and Negative SF (NJT)

What stays the [b]same[/b] and what [b]changes[/b] as you move [br][list][br][*]the slider (SF)[br][*]the centre[br][*]the vertices A,B,C?[br][/list][br]Are there any points that do not move under this transformation?
[color=#0a971e]Created by N.Trubridge[/color]
– oliver_sophist, Nicola Trubridge

Information: Copy of Enlargement 3 Fractional and Negative SF (NJT)