@b3m2a1 Wow, these iterators act like references, i.e. if I do it2 = it then I Read@it, then both it and it2 change.

Of course it's clear why, but something like this is unheard of as a documented Mathematica construct

Which is a pity, really.

This looks like another situation where a state object would be necessary: mathematica.stackexchange.com/q/204695/12

@CATrevillian There is an undocumented function GraphicsPolygonUtilsPointWindingNumber, which works on non-closed curves. Playing around with it, it looks like it gives a value of 1 for an arc of a circle if it is at least half the circle. My guess is that it is joining the endpoints with a straight line to make a closed curve.

If someone found that my question is a duplicate, should I just delete it?

@ChrisK I would say no, since your wording may be different and may help someone else get to the answer via your question.

yeah I also linked to it in a bugs report to WRI, so maybe leave it

can't vote to close either, since the original is unanswered

As far as I can tell, adding "Wolfram Language" to the logo is still not clear enough to prevent users from asking here what they should be asking on math.SE.

Also, it's september. I'm seeing homework questions already

@C.E. if I had to generalize it's the askers with somewhat more limited English ability who tend to ask plain math questions here. Not sure whether adding the Wolfram Language would help with that in any case.