Posting here, since the other thread was ninja vanished:
Consideration:
1. Last I checked, a 'circle' was a 2 dimensional geometric mental construct and would most definitely be 'flat' [an imaginary 2 dimensinal plane] - See:
2. Last I checked, even when a 'circle' is drawn on paper, even with the thinist ink [even a computer pixel drawing as linked above], etc., it then contains a depth, and is not longer truly a 'circle', but now a hollow cylinder [like a pipe] [as it now has 3 dimensional depth, even if miniscule].
3. Last I checked, even the flat-earth models are not a 'circle' as such, but are varied 'cones', 'chips and dips bowls', 'terrariums' [with spheroid or domish surroundings, or other], all of which have
more than their stated "four corners", as such cubish that have
8 corners.