zipper bangle cane
polymer clay central has an easy zipper cane tutorial: www.polymerclaycentral.com/zipper_cane.html though i altered this by following the tutorial up to step 5 then squashing and lengthening the log until it was 2in wide, 6+ inches long and about 4mm thick.
i then put a sheet of white polymer clay through the thickest setting on my pasta machine (mines only got 7 settings so use your judgement here ) place the flattening log on top of the sheet of white (make sure the sheet of white is wider and longer than the log!) and run through the pasta machine again. i cut strips from this sheet and stacked them as in step 9.
if you want thicker white stripes simply roll out a sheet of white and alternate between a strip of white and a slice of the coloured sheet when stacking.