Flag semaphore
Flag semaphore (from the Ancient Greek σῆμα (sêma) 'sign' and -φέρω (-phero) '-bearer') is a semaphore system conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags; it is read when the flag is in a fixed position.