swapTailHead.gvpr - a gvpr program to swap the head & tail of an edge (really, it deletes the old edge & creates a new edge w/ swapped head & tail). Surprisingly messy.
By default, it will also swap all the head and tail attributes (e.g. tailclip, arrowtail, headport, …).
It is modestly tested, bugs probably still lurk.
It does not seem to have much impact on non-dot engines. (I guess they don’t care much about heads & tails)
A fun toy (see below), but “is it a thing?” Not sure.
Some examples, unswapped & swapped:
