Semaphore

Semaphore is a signalling system which involves waving a pair of hand-held flags in various positions to indicate letters of the alphabet or numerals. The flags used in modern semaphore are usually square, red and yellow and divided diagonaly with the red part on the top left. Semaphore in various forms has been used to send messages over distances since at least Roman times.

Semaphore

Links

Free semaphore graphics
http://www.nwsc.org/graphics/semaphores.shtml

Text to semaphore convertors
http://www.scouting.org/fun/semaphore/
http://wxs.ca/applets/semaphore/ (animated Java applet, slow to load)

Other communication/notation systems

Braille, Maritime Signal Flags, Moon, Morse code, Semaphore