During my first course in calculus, Ambjörn the TA was going through whatever it was and I innocently asked “Isn’t this, like, fractal?” He spun around: “Yes, exactly!”, spun back towards the blackboard and proceeded, chalk blazing, to explain how the current course segment was tied to fractals, their implications for geometry and how that in turn related to other branches of mathematics, ever faster and further into ever more exotic subjects while we students could just hold on to our desks for dear life in the storm blast of imparted knowledge. Forty-five minutes later he suddenly made a double-take, checked the time, and with an embarrassed cough noted: “I think we ran over the time a bit there, let’s take the break now.”
During the break Å accused me of setting Ambjörn into self-oscillation and suggested I shut up in the future, lest we never manage to cover what was actually coming on the exam.
Well, I did pass the calculus exams, eventually even the dreaded Theory exam, though that took me five attempts (in no way an exceptional number). Still, perhaps that was more due to diligently doing all exercises and repeatedly reading the books, rather than thanks to Ambjörn’s TA efforts, which, while always entertaining and mind-opening, tended to veer off from the official subject into Deep Maths.
Eventually I became a colleague of Ambjörn’s, whose wide-ranging interests could no longer be contained within either the Department of Mathematics or that of Physics and thus had moved into Computer Science (which at the limit contains all other sciences). Passing his room would often imply getting drawn into impromptu lectures on maths and their relation to everything else in (and occasionally outside) the universe. He even stored some of his parabolic rock-melting mirrors in our lab, though we irreverently ended up using them as towel racks.
Today, Ambjörn was officially retired, though, as is the custom in academia, that simply means the end of salary, but not necessarily the end of research. So, I returned to the Alma Mater for Ambjörn’s Last Lecture, which, true to form, ranged from how to explain what weekday it will be in a million days, over homotopies of snakes on a torus, to how human culture is an integral over time.
I regretted Honeybuns wasn’t there to get some kind of idea of where I come from, intellectually, but the OBCM was there and afterwards we had a nice chat about teaching and geometric modelling over a cuppa.