US Patent 7699698 Gaming machine and method involving a selectable bonus evaluation system

A coin-operated player operable entertainment machine has a main display device, such as rotatable symbol-bearing reels, which selects a combination of symbols at a win zone after a game-play stake has been credited. Some symbols are bonus symbols which can initiate a bonus feature if at predetermined win zone positions. The game-play stake can be changed by the player to change options for attaining the bonus feature. The arrangement may be such that an increase in stake value results in an increase in the number of predetermined positions which correspond to initiation of the bonus feature.