I find that dots work well in games that are slower. For this game you'd want something that is very easy to be distinct very quickly, stripes are better for that, but you'd run into the issue that you have 12 colors. An easier way to get around this is by letting the user choose the colors of the icecreams themselves, that way I can choose colors that work for me, and someone with a different colorblindness can do something different.