A small problem of national treasure 1

One comes from the land and two from the sea.

It was during the American Revolutionary War that an observation point was set up in Boston to prevent the British from landing from the sea or suddenly attacking from the land. Once the British navy is found, a lamp is hung, which is equivalent to the beacon tower in ancient China.

On the way to Lexington, the British army found dozens of villagers standing on the grass outside the village, with spears in their forehands. Smith knew that these armed villagers were the militiamen who came to Lexington, and the residents of the colonies in North America called them "one-minute people" because they acted very quickly. As soon as they heard the alarm, they could gather together in a minute and immediately go into battle. To Smith's surprise, why did these militia know about the British action so quickly? It turned out that the scouts of the "Communication Committee" had got the information and immediately hung a red light at the top of the Boston church. Paul riveire, the messenger of the "Communication Committee", immediately rode to Concord to call the police.