books.google.ca - Did the Masons encode messages in walls—and even in the street plan of Washington, D.C.? Does the Hebrew Bible conceal hidden mysteries? Ingenious methods for encoding secrets have taken many amazing turns through the ages, from the military signals the Romans flashed from hilltop to hilltop, to the...http://books.google.ca/books/about/Hidden_Codes_Grand_Designs.html?id=F9q8BAsXTWEC&utm_source=gb-gplus-shareHidden Codes & Grand Designs
