What I'm trying to make, is the opposite of that, meaning the lines bend inward to looks something like:
I achieved that by making three circles, but it's a pain to align the third circle properly.
I'm sure that there's an easier way to make a shape like this. (geometrically)
It's pretty easy to make this with a 4 sided (diamond) Just lay out four circles in a box (smart guides make it take a second) and cut out the center.