A utility patent protects how an article functions (35 U.S.C. 101), and a “design patent” protects the way an article looks (35 U.S.C 171).
The ornamental appearance of an article includes the shape/configuration or surface ornamentation applied to it, as well as any combination thereof.
A design patent protects the unique visual qualities—such as shape, colour or texture— of a manufactured item. A design patent is granted if the design is original and has not been produced previously. It lasts for 14 years from when it was filed, and allows an inventor to develop a new way of using an existing product.