US Patent 10176668 Games and gaming machines having game symbol replacement feature

A slot-type game and a gaming machine configured to present a slot-type game include a symbol replacement feature. A first set of game symbols is displayed. If a replacement symbol triggering event occurs, such as the appearance of at least one replacement symbol, the symbol replacement is triggered. At least two symbols of the first set of symbols, such as two symbols adjacent to the replacement symbol, are evaluated to determine a highest ranking and a lowest ranking symbol. A second set of symbols is then displayed, the second set of symbols comprising the first set of symbols with occurrences of the lowest ranking symbol replaced with the highest ranking symbol.