In an information code which is arranged to redundantly code at least one first information element by means of a first information element, one or more of the marks can be omitted for the coding of at least one additional information element. In addition, copy protection can be created for an information...http://www.google.ca/patents/US20050173533?utm_source=gb-gplus-sharePatent US20050173533 - Information code including redundant information providing copy protection
