Challenge your mental skills while having loads of fun! Duncan's Color Shift Puzzle ball can be solved by matching all of the colored balls with their corresponding colored rings. There are 8 holes with only 7 filled with a colored ball. Utilize the empty hole to maneuver balls around to find their matching hole. Once all balls match, the puzzle is solved! How fast can you do it? Hours of fun in the palm of your hand! Great for the beginner puzzle-solver!