That example worked better in my head

but hopefully you can see that to say the circle is ambiguous, logically entails that there is not one authoritative list of contents. There are multiple, equally valid (unable to be chosen between) ways to draw the circle. And that doesn't change just because there are things that on all accounts are put outside. The language is deceptive. We casually spoke of a circle, but seeing that circle is ambiguous we must hold in mind that it comprises multiple overlapping circles, all equally valid - no definitive way to choose between them.