Miraculous …

… How Tolstoy's 'Anna Karenina' Saved A Political Prisoner's Life In Somalia : Goats and Soda : NPR. (Hat tip, Dave Lull.)

… one night, eight months into his prison sentence, as the guard is passing just out of earshot, an inmate in the next cell whispers to him. He says, "Learn ABC through the wall."
"I did not understand," says Mohamed. He looked at the wall between them. Then he heard some knocking.
It was a code.

Anna Karenina is more than 800 pages, about 350,000 words, nearly 2 million letters, each letter a set of taps. So the doctor wraps a bedsheet around his hand to protect it.

"So then I started knocking, and he started listening."