technique called Mokume Gane. 2 tutorials in polymer clay. http://www.sculpey.com/project/premo-mokume-gane-bubble-neckpiece/ http://beadsbylhox.yolasite.com/tutorial---how-to-make-mokume-gane-clay-beads.php colored soap in 4 different colors and poured them into the mold at light trace in layers. used different tools (pieces of cardboard, cocktail straws, paper tubes, etc) to push each of them into the poured soap. makes colors blend down through one another in layers.