A sales promotional system includes a first sheet having an incomplete check having certain information missing therefrom. A participant obtains the missing information (e.g. by purchasing a designated product or service) and, if the information matches the check, adds it by hand to the first sheet to...http://www.google.com.tw/patents/US4630844?utm_source=gb-gplus-share專利 US4630844 - Two-step bank draft
