Canes, or millefiori (if you prefer fancy words), is one of the most popular techniques for polymer clay. Adopted from the ancient art of glass-making, it suits polymer clay perfectly.
Charlene (Cat) Therien is probably one of the best masters of this technique. At her shop, you may find not only her beautifully-detailed raw canes, but also tools and tutorials for making and slicing your own canes.
Visit Cat's web site to see more of her work and to find a list of her free polymer clay tutorials.