I first experimented with carving the stamp before the Sugru had cured. Prepare the stamp as in Step 2. Using a nail and a utility blade carve a shape onto the stamp. The Sugru is quite soft at this point so it is easy to carve and if you make a mistake you can just smooth it over and start again. It is important to make the lines thick enough and keep the surface even. When you're satisfied with your stamp place in a warm dry spot to cure for approximately 24hrs.