For children and adults at the very beginning of learning their reading and writing skills, adding texture can make the experience more interesting and fun. When you move your fingers around the shaped slots each texture will give you a different feeling. If you like the feeling you are more likely to do it again. Repeating and reinforcing the movement in your memory and your muscle memory. If you are a more active learner, the action of movement while looking and writing the shapes can help you remember and make easier the task of writing. It can be used hand over hand or using a tool to give you the sound and vibrations as you move around.