A blonde bought two horses, but could never remember which was which. A neighbor suggested that she cut the tail of one horse, and that worked great until the other horse got his tail caught in a bush. It tore just right and looked exactly like the other horse's tail. Our blonde friend was stuck again.
The neighbor suggested that she notch the ear of one horse. That worked fine until the other horse caught his ear on a barbed wire fence. Once again our blonde friend couldn't tell the horses apart.
The neighbor suggested that the blonde measure the horses for height. When she did, she was very pleased to find that the white horse was a full two inches taller than the black one.