The telegraph could, of course, save many keystrokes — infinitely many, in the long run — by simply sending the messge "π." But this is a cheat. It presumes knowledge previously shared by the sender and the receiver. The sense has to recognize this special sequence to begin with, and then the receiver has to know what π is, and how to look up its decimal expansion, or else how to compute it. In effect, they have to share a code book.