The rule
The pen doesn't leave the paper. That's the whole method, and it's harder than it sounds. No corrections, no second pass — the hand commits before the head can argue.
She draws fast, usually with her eyes more on the subject than the page. The good ones happen in under a minute. The rest go in a drawer nobody opens.
If I can see the line working, it's already dead. The point is to not quite know what I've done until it's done.
What comes out isn't a likeness. It's closer to a transcript — the shape of an afternoon, a posture, the particular way someone holds boredom or grief. Reference would only get in the way.