See samples of hobo signs. https://www.nsa.gov/about/_files/cryptologic_heritage/museum/library/hobo_signs_definitions.pdf https://www.nsa.gov/about/_files/cryp

See samples of hobo signs. https://www.nsa.gov/about/_files/cryptologic_heritage/museum/library/hobo_signs_definitions.pdf https://www.nsa.gov/about/_files/cryptologic_heritage/museum...