The pillar next to the whiteboard is covered in little white rectangles, a laid-out record of lecturers cleaning off accumulated dust from saturated erasers. The erasers soak up notes and notes and notes, narratives and symbols and enactments, diagrams and relationships, sketched out in a dust that was dug and refined from some hillside, formed in the ground many years ago.
The stories of the clearest theorems are far from simple. There are many conflicts, many subtleties to the notations chosen, controversies about priority and reliability. As a simple piece of terminology, a name, is deployed, all of this history puffs into a sentence; just a beat in the flow of a lecture, but lifetimes in the making.