Swaping Pivot Point on Arc 3Pts before next rotation

Hi all.

One of my students asked me to help him to find a way to setup a GH definition so that he will be able to rotate an Arc 3Pts interactively by defining on the fly one of the Arc Ends Point as a Pivot Point.

Below is a short video showing a side by side approach.
Left - Grasshopper - Explicit définition for new Pivot Pt before next Object Rotation.
Right - Rhino : User can choose any implicit End Point before next Object Rotation.

Attached are the example files he is working on.

Pivot Point Swaping.3dm (2.0 MB) Pivot Point Swaping.gh (13.9 KB)

The actual definition is iterative meaning that before any new rotation, the wanted pivot point needs to be explicitly defined which is accumulating lots of components.

What is asked is to be able to manipulate the object Rhino Like via controllers in the context of Grasshopper, sort of dynamic update of available End Points on the transformed object…

Does any of you have a suggestion to approach this problem with Grasshopper ?