Alphabet Tracing with In App Purchase

We have couple of Alphabet apps in the appstore. Now we want to develop an alphabet writing app for the 33 letter alphabet. This app will have two main features. 1) Illustrations - How to write the letter: This illustration need to be very creative. Instead of filling the color in the letter, we need to draw the letter with materials for instance flowers, water, bubbles, rails, road with appropriate sounds just to give you an idea. But you can come up with materials you think will be attractive. (Check letter school letter writing app) 2) Practice - User will start letter writing. Using the same type of material, the user will be able to write the letter. After completing the first 11 letters, there has to be creative way to reward the user. Further this has to come with In App Purchase feature. First 04letters will be free and user will have to pay for the full version.