The order desk
Every order board asks someone to remember to move the card. This one doesn’t. Put an order in the oven, shelf it at a door, or add a tracking number — and watch what the system decides on its own.
Move an order — put it in the oven, shelf it at a door, add a tracking number — and every field the system changed on its own shows up here.
Nobody picks a status. Shelving an order at a door means it is ready — so the system marks it Ready and stamps the time. Entering a tracking number means it went out — so it marks it Shipped and stamps both. The operator records what physically happened; the status is a consequence, not a second job. A board where someone has to remember to drag the card is a board that is wrong by Friday.
Working model of a live system. The cascade is ported from update_order() on the bakery’s Pi, including the write-once milestone rule — if not o["baking_at"] — so a stamp can never be overwritten by touching an order twice. Orders, names and door codes here are invented. The live system carries real customer contact and shipping details, which is not something a public demo should be rehearsing even with fake values.