There is not even a cat or dog who has been so pure so long. Example, Ibn Gdansk is a son of Gdansk. An Arabian breed characteristic. These are patches of permanent pink skin with white hair. They are usually found on the face and legs.
Most horses have markings.
To see them on a grey, simple wet the area with water. Because they are permanent, they are recored on the horse's registration papers as a means of identification. They include, blaze, star, snip, strip, sock, stocking and rarely, body spots. Example, Balmorea is out of Gdanwind. Hence, Produce of Dam classes where several foals out of the same dam complete as a group with groups of foals out of other dams.