Feature:In the back of each puzzle,it is different color pattern,show number 1 to number 100,can guide kids to finish the puzzle.
Features:
Easy to storage:A free iron box for easy storage.
Easy to distinguish:There are numbers and different colors on the back which is easy to distinguish where are they belong to when the four puzzles were mixed by your little baby.
High density drawing sheets:All of the pieces are made of high density drawing sheets which is healthy and sturdy.