Having like size beads is good, so begin by measuring clay for beads. Using a tube bead roller top, roll some lengths of clay. Pick a color that will end up being a center color in your swirled bead.
Using a measuring guide, ruler with raised increments, or other clay marking tool, impress lines in the tube of clay. Now you have reference points to cut specific amounts of clay to keep beads at a consistent size.
Hand roll the measured amounts of clay.
Roll two tubes of contrasting color, lay them side by side. At this point you can roll over them a bit with an acrylic rod, to get them to stick together.
Run the tubes of clay through the pasta machine. Fold in half lengthwise, and run through the pasta machine, folded edge first. Repeat this until you like the appearance of the blending in the center.
When you like the blending, roll the blend thin. Now you are ready to cut circles out of the blend as shown and apply them to either side of the hand rolled ball.
With the circles of color attached, place the roller top over the clay as shown, with the base clay color in the center.
Begin making a circular motion with the roller top. Continue rolling until the colors swirl in an appealing pattern. Keep the circular motions going in the same direction. The tilt of the roller top, the pressure applied and the circumference of the circular motion all can have an effect on the bead, so if you haven't done this have some fun getting the feel and practicing. Well worth your time, guaranteed to please!
Once you've gotten the swirl you like, you can use the roller top to apply pressure to change the shape of your bead. The two center beads in this picture were made rectangular in shap, simply by putting pressure on one sice with the roller top. Fun!!!!