Transparent blank symbols are disposed on each of first, second and third display parts respectively provided in first, second and third display plates. The player wins if the same symbols of the first to third display parts are arranged in line on any of winning lines when the first to third display...http://www.google.co.uk/patents/US20040183251?utm_source=gb-gplus-sharePatent US20040183251 - SYMBOL DISPLAY DEVICE FOR GAME MACHINE
