Teff - A One-Horse-Powered Lawnmower Here is the coolest, most "green", one-horse-powered lawnmower anyone could ever have! This is Teff, our 6 year-old, miniature, "sea"-horse. Since we got him at 8 months old, he has kept the lawn on our lighthouse station mowed beautifully. How does he travel, you ask? He's been by both ship and helicopter and takes either mode of transportation quite in stride.