Stacks Puzzle! - 3M Game of Color Rings. This is a very simple and relaxing game of color circle and stacks. It's combined from match 3 games and color lines. In the other way, you could see it's familiar to XOXO games Tic tac toe. User have to put the color rings on one in nine stacks on the board. One spot can stack maximum 3 rings in different sizes, color doesn't matter.