Conventional puzzles: there is no bottom plate, give the baby a few pieces and a drawing, and spell it directly; It requires a certain amount of spatial thinking, which is far more difficult than interest for babies who have just come into contact with puzzles. Cardboard puzzle: with its own bottom plate. When the baby is new to the puzzle and lacks spatial thinking ability, he can sit one by one in front of the pieces that have been divided on the puzzle board. In this process, he can know up, down, left and right, and cultivate a sense of space appropriately.