The mysterious Mona Lisa could use a little grooming—so go ahead and brush her long black hair! Continue with the Old Masters by touching the large, lacy collar of Frans Hals’ The Laughing Cavalier, petting the horse’s tail in Velazquez’s Prince Baltasar Carlos on Horseback, and arranging the snappy elastic hair in Boticcelli’s The Birth of Venus. Other paintings come from Vermeer, de la Tour, Raphael, and Van Eyck.