Perfect circle every time. Remember just because you have never seen it done before doesn't mean it hasn't. I have used this method several times including once when I cut 2 inches of glass and epoxy. (link below) ...
by MrUsegoodART
by MACRAME MAGIC KNOTS
by Ann Benson
by Etsuko Watanabe
by Ingleton Pottery
by theartsherpa
by specialCANmade