... As I trudged up the hall steps of 221 B Baker Street, my attention was drawn to the door of our flat. Someone had written the letters QZHDF LPCIE OAKXC MRVMT in chalk across the upper panels. I had not the least idea what this mysterious message meant, but concluded that it might be some sort of cipher.
Eckler, A. Ross
"The Case of the Ambiguous Cipher,"
Word Ways: Vol. 3
, Article 14.
Available at: http://digitalcommons.butler.edu/wordways/vol3/iss4/14