Related to this question, I've tried to understand how triangles are interpreted in Blender.
Doing these experiments, the result is a bit surprising and I'd want to know why.
Starting from a quad, I obtain this (see gif below): kind of convex hull is calculated and the faces are overlapping only for first and third vertex in fan point of view:
But if we test that for a polygon with more than 4 vertices, it does not happen anymore:
Surely, I've not tested it for all configurations (all vertex amount), but it seems to be a rule.
Why? And, by the way, how this behavior has a link to my original question?
In hope the title of this new question is good enough, this time, thanks for any information.