LAW OF FASHION doesn't discuss design patents very often (though an entire chapter of this writer's forthcoming Oxford University Press treatise, Intellectual Property Protection in the Fashion Industry, will be dedicated to the subject.) So LOF suggests that you check out this article from the University of Pittsburgh Law School's Jurist, which discusses the recent case of Lululemon Athletica Canada, Inc. v. Calvin Klein, Inc. (D. Del.), brought over the alleged infringement of three of Lululemon' design patents in multi-waistband yoga pants:
The Jurist article, in addition to introducing the Lululemon lawsuit, covers the basics of design patents, which, as the student columnist notes, are properly used to "protect [a] manufactured article's non-functional, [novel and non-obvious] ornamental features, [but] have long been an underutilized source of protection for patentable goods."