An excerpt about Telegraph Hill which might appeal fans of historical code systems:
In 1850 a semaphore, called the Marine Telegraph, was placed on the hill's summit to inform the city when ships came through the Golden Gate—hence the name Telegraph Hill. The various positions of the semaphore's arms denoted different types of vessels and were widely known by San Franciscans—a fact that resulted in one of the best one-liners ever delivered in the city. During a Gold Rush-era performance of a play called The Hunchback, an actor entered with outstretched arms, loudly declaiming "What does this mean, my lord?" Before the other actor could respond, some wag in the audience shouted out, "Side-wheeler steamer!," bringing down the house.