Anna Jour's hollow bead - use paper tissues for the base - make a tight paper ball , then cover with clay, make holes and bake. After baking soak the beads in water and remove the paper using a skewer or a needle, or a crochet hook.
Jan Geisen wrote an article for the December 2011 issue of Polymer Cafe magazine called An Introduction to the Principles of Design. Included with the article were templates and excercises for artists to try. Jill Palumbo sent Jan the above photo showing her experimentation with the templates.