This is a 631-piece puzzle from Ravensburger that is the image of simple colour gradients in shades of yellow, green, blue and purple. It is an excellent way to put one's colour perception to the test, allowing one to explore their ability to differentiate between various hues. These beautiful pieces of puzzles have been created using a hand-crafted spiral-shape cutter, ensuring every puzzle piece is different from the other. They have been made using the soft-click technology, which makes a clicking noise on joining two accurate puzzle pieces. Thick cardboard coated with linen-structured paper has been used in doing puzzles, ensuring durability and a glare-free clear image. Once the puzzle is complete, it measures 70 cm x 50 cm. Puzzles help develop memory skills and are great for children and adults to indulge in during their free time. It can be put together alone or with friends or family members. When the puzzle is complete, it can be framed or taken apart and saved for the next play time. This amazing puzzle kit will make an excellent gift for children who are looking forward to a surprise on their Birthday, Christmas, Easter or other occasions. Ravensburger Puzzle 631 Piece Krypt Gradient is recommended for adults and children ages 14 years and above.