A slot machine. In one embodiment, a given symbol is included in each of a series of symbols, and a judgment device is provided for locating the positions of a plurality of given symbols appearing within the windows but not all on the prize-winning line, after all the symbol series have stopped. Provision...http://www.google.com/patents/US4826169?utm_source=gb-gplus-sharePatent US4826169 - Slot machine with a marker symbol
