Having trouble finding reflex vertices of a polygon

[COOLDEV16T (DevDaz)]

I’m following this tutorial

Reducing polygon(s) to rectangle(s)

Recently I was searching for ways to ‘rectangulate’ rectilinear polygons too. I already came up with a way of doing it but I’m browsing the forum to see whether there are any alternative solutions. I’m sharing what I have here to see if it fits your needs since you said that rectangular decomposition was not the exact solution you were looking for. So let’s get into it. Assuming that the placed nodes are either in clockwise or counter-clockwise order and that the polygon is rectilinear with mo…

on decomposing rectilinear shapes into rectangles and I’ve got every step figured out except step b with says to find the reflex vertices of the polygon which I have absolutely no idea how to do