1The worms may go through the hole in turn or in the opposite order until the string is untied. 2In the process of playing, children can learn the concept of inner side and outside, and training their hand-eye coordination. 3Training the hand to fine movement control, but also can exercise children's reverse thinking. 4Made of quality wood material, not easy to deform, durable and reliable. 5There are 3 different styles available, you can choose according to your needs.