Cylindrical in shape, used to make a cyphered text by wrapping a piece of paper around it. The user writes a message on the paper and sends it off to the receipient, who, in order to decypher the text, has to have a cylinder of an equal diameter.
Said to have been used by ancient Greeks and Spartans to transport encrypted messages across the battlefield to avoid having their secrets fall into their enemies' hands.
2. Bene tleilaxu face dancer & assassin / tleilaxu master featured in Frank Herbert's literary masterpiece Dune. Makes his first appearenace in Book 2, and an unexpected and mysterious comeback in Book 6.