Not every message requires the messenger to wait at the castle gate. A traveler arrives at the castle gate with an urgent request. The guard carries it to the steward, the steward consults the royal records, and the traveler remains outside until someone returns with an answer. This arrangement works when the traveler needs an immediate response, and the castle can provide one quickly. It becomes fragile when the work takes several minutes, the responsible official is unavailable, or five hundred travelers arrive at once. The problem is not that the road is poorly built. The problem is that every participant must remain available throughout the conversation. In the previous…