This surfaced again recently.
Here I am in 2011(!) drawing on the wall of a cafe in King’s Cross, Sydney (Coco Bar, I can’t find that it exists anymore). I’d been staying in a youth hostel across the road and sketching while having coffee each morning, and the cafe staff kept asking me to paint a mural. I kept saying no, I was leaving soon (and hadn’t done a mural). Then they came out one morning with a permanent marker and said, “Free coffee until you leave,” and I bargained them up to free daily coffee and pain au chocolat, and then freehand-drew the picture directly on the wall.
This, incidentally, is still the best way to get me to do most things: trap me in the location, feed me, and don’t let me out until I’ve done the thing.
Here’s the page of the sketchbook I am using as reference in the photo.