How to Keep Polymer Clay Forever - Polymer clay will stay soft for a very long time under the right conditions. It doesn't dry out in the air, and if it does get dry, it can be softened using special products. - bjl
Mosaic cane tutorial: Make short logs of colors of Premo or Fimo clay. Wrap each log with thin blanket of lighter color clay. Stack the covered logs and press together to form a new log. Slice in half and wrap uncovered edges. Repeat. Repeat. Repeat. Add depth & variety with thin layers of translucent clay.