I studied math and knew a girl like that, spending an inordinate amount of times making sure to understand every single details of what we were taught, even going further when I could barely keep up. She would also make those pretty, colorful notes with visual interpretations and drawings in the margin. It takes a special form of love for the discipline. She just finished her PhD and is now starting a postdoctoral contract.

Looks like a prepared presentation rather than notes.

If all presentations were prepared like this I’d probably attend them

Indeed. All presenters can take a lesson from this talented person.