A lottery card comprising a given number of fields, arranged in a successive order. Each field is divided into a given number of frames. At least one of the frames of every field contains a mark. All marks are related to each other according to a successive order, and are concealed by being coated...http://www.google.de/patents/US5690367?utm_source=gb-gplus-sharePatent US5690367 - Lottery card and method
