This is called Persistent Imitation.

The child sees before him some action to imitate--some complex act of manipulation with the hand, let us say.

He tries to perform it in an experimental way, using the muscles of the hand and arm.

With this he strains himself all over, twisting his tongue, bending his body, and grimacing from head to foot, so to speak.

Thus he gets a certain way toward the correct result, but very crudely and inexactly.