Clacks a discworld board game is based on the quotclacksquot semaphore messaging system mdash the fastest non magical messaging system on the discworld mdash featured in sir terry pratchett39s novel going postal using a semaphore system of shuttered lamps on top of high towers the grand trunk semaphore company has revolutionized long distance communications on the discworld their network of towers covers most of the unnamed continent but now the old postal service is fighting back dr