Then the one, having neither beginning nor end, is unlimited?

Yes, unlimited.

And therefore formless; for it cannot partake either of round or straight.

But why?

Why, because the round is that of which all the extreme points are
equidistant from the centre?

Yes.

And the straight is that of which the centre intercepts the view of the
extremes?

True.

Then the one would have parts and would be many, if it partook either of a
straight or of a circular form?

Assuredly.

But having no parts, it will be neither straight nor round?

Right.

And, being of such a nature, it cannot be in any place, for it cannot be
either in another or in itself.