In 1989, when I was doing my undergraduate project at the Institute of Sound and Vibration Research at the University of Southampton, I gained access to the magical room that contained two Mac SEs and a Mac IIx (no Windows on PCs back then). The Mac IIx had a copy of Mathematica on it and I was enthralled, even though I didn’t need it for my project. Gradually word spread that I was using it and everyone’s mathematical problems started finding their way to me, including one to do with modelling shock waves in kidney stone lithotripsy. I wanted to spread the word, so I wheeled the Mac to a lecture room, connected it to an LCD viewer that sat on an OHP (no data projectors then) and gave my colleagues a talk about what it could do. I only understood a tiny fraction of its capabilities then, and that’s probably still true today, given the rate at which it has grown, but it’s enough to keep me regularly turning to it for problems I couldn’t solve another way.