During the meeting of Ankh-Morpork's leaders, the Dean of Unseen University protests against Leonard's invention, stating that they have no assurances other than his word that it will work, citing Bloody Stupid Johnson as an example of the unreliability of inventors;
"Show me one thing he can do that anyone couldn't do, if they had the time."
"I have never considered myself a genius," said Leonard, looking down bashfully and doodling on the paper in front of him.
"Well, if I was a genius, I think I'd know it-" the Dean began, and stopped.
Absent-mindedly while barely paying attention to what he was doing, Leonard had drawn a perfect circle.