The coats of domestic dogs are of two versions: "double" being common in dogs (as well as wolves) originating from colder climates, made up of the coarse guard hair plus a tender down hair, or "solitary", Using the topcoat only. Breeds could possibly have an occasional "blaze", stripe, or "star" https://deanibocx.blogminds.com/dogs-can-be-fun-for-anyone-29265740