One of the most unique 3D puzzles I have ever seen. Each of the four cubes included has a unique color and setup of snake shapes, used in combination to create a snake of specified standards. The challenge booklet includes several levels of difficulty: A. is for practice, with the colors, position, and snake shown on the puzzle. B. leaves only the colors and positions of the cubes showing. C. takes the game a step further with a mix of colored and non-colored blocks positioned. D. combines the challenge of all three, with just the position of the blocks shown. Of course, if you get stuck, there are solutions in the back. This puzzle is a good mental challenge for all ages.