What makes you say that? The circle is one of the few familiar objects from grade school geometry which is also an algebraic variety. Also, where do you see th

What makes you say that? The circle is one of the few familiar objects from grade school geometry which is also an algebraic variety. Also, where do you see that quote in the article? The only part about circles I saw was the description of the tangent bundle of a circle. This is exactly the kind of example one might see in a first course on differential topology, so I don’t see the issue.