The courtier asked each artist to create a sketch to send to the pope to be evaluated. When the courtier visited Giotto, now considered to be the first great master of that era, Giotto "took a sheet of paper and a brush dipped in red ... and with a turn of the hand made a circle so even in shape and outline that it was a marvel to behold."
The courtier thought he was being ridiculed; Giotto insisted on sending only that drawing to the Pope.
He won the commission.
Giotto's O is a fantastic symbol of virtuosity. What would be the equivalent of Giotto's O in other domains? What would be a simple demonstration of mastery?
It is easy to imagine equivalents in athletics: Pele juggling a soccer ball, for example. But what about academic skills? What would math virtuosity look like?