Descr1: 1. A person rides a horse down a hill
  2. The horse lifts its fore legs and is positioned vertically
  3. The horse continues running with only two back legs
  4. The horse reaches the bottom of the hill and returns to normal
Descr2: 1. The player is riding a horse on a trail
  2. The horse stands upright while running
  3. The horse stops running
  4. The horse stands back on all four legs