Really? African proverb? According to whom? Furthermore, lets stop referring to things as simply African. It'd be as silly as referring to something as simply Eurasian. If this quote does legitimately hail from Africa, what country or countries?
So What Does One Leg Mean - It turns out that this is a myth. It originated with the markings on Indian ponies. A circle around the eye meant better eyesight, around the nostril, better sense of smell, a red handprint on the flank: the owner died in battle and sent the horse home with a slap to its rump, leaving the "bloody" handprint.