This shit is too interesting…
http://craymond.no-ip.info/awk/ttcode5.html
From the page:
"For example, suppose !Alice! wants to encrypt a message using a Vigenere cipher with the cipher !key! word "WARTHOG". To encipher the first letter, she moves the "W" on the inner disk to match up with the "a" on the outer disk, and then finds the ciphertext letter on the inner disk matching the desired plaintext letter on the outer disk. "