Teammates Tyler and Stephanie constructed a low communication alphabetic based system "capable of flexible sending of messages at a distance of 600 yards and beyond." The system did not rely on electric components.
The communication system was composed of four signs with four different symbols, that when rotated (like a clock face) would represent a different letter of the alphabet.
The fourth sign was aU which either meant repeat or end the message.
Learn about this project and more about the CIA program