His sketchnote-as-timeline idea made literal: a sticky left ledger that GROWS as you read. Every chapter you pass and every line you mark adds an entry - by the end of the page the ledger has BECOME the sketchnote timeline of your own reading, sitting beside the booking form. The most koanloop of the four.
1. The ledger unifies v1's two best organs: the timeline spine AND mark-and-return become one object.
2. It answers verbaltovisual's question exactly: the sketchnote timeline exists, and the READER co-draws it.
3. Arriving at the form, the visitor sees their own journey summarised: the koanloop thesis at its purest ("the site develops YOUR thought").
4. Passive readers still get a ledger (chapters log themselves); marking enriches it. Nobody reaches the end empty.
5. One ground event; ledger entries stay greyscale except the single hot shift entry.
6. Risk: the ledger must never feel like surveillance or a progress bar (his anti-vote); entries are handwritten-toned, few, and deletable.
7. Mobile: ledger compresses to a top strip with count + expand; full ledger reappears at the form.