I like to match my jewelry to my clothing, and I wanted something for jewelry with a tad of a certain purple to wear, so I used just a small amount of the purple clay with the Fimo silver effect clay, to make the swirl. It's a great thing to do with left-over clay! I twist together a small coil of one color, and a larger coil of one or more other colors. Then using a piece of glass, I swirl the clay around to create the swirled effect.
