Extensively marked horses have a pattern of white hairs that seems to extend out from the flank as well as numberous white hairs at the base of the tail. The edges of the white areas are crisp and distinct like tobiano spots, but the head is largely white, and varying extents of the belly are white. The eyes are commonly blue. Some blankets have roan edges, blending into the colored areas. Other blankets are solid white and sharply defined, and still others blend into the colored areas with flecks of white hairs.
Many blankets show characteristics of all three and is difficult to cleanly separate the types.
These spots can vary in size. This pattern will likely change with the age of the horse, since many are born solid and develop this pattern later in life. It begins with small spots that grow into the coat of a colored horse. The white spots can increase in number as the horse ages until the pattern stabilizes at some point. Mottling can occur over the entire body in a pattern that does not fit into any other pattern of white.