http://www.quiltingboard.com/posts/list/16797.page
read all of it
you can also make your own by tracing one you like on paper, pinning it to your quilt and sewing right over it. you'll have to trace enough to go your whole length. you might be able to use spray adhesive, but i never have tried that. also, i used see-thru plastic wrap instead of paper. it's all a matter of preference. whatever you use, you have to pick out the bits when you finish.