text: Yo, listen up, let me tell you 'bout some tech
  Autonomous robots and vehicles, they gotta check
  Recover from locomotion failures in granular terrain
  NASA JSC's got a prototype, they call it RP15
  
  It can wheel, it can crawl, and it can even use its legs
  To move around on the moon, no need to beg
  We developed a scaled-down rover to study its performance
  On slopes of dry and wet granular media, we got the evidence
  
  With a cyclic-legged gait, it changes from wheeled to a paddler
  Like swimming through frictional fluid, it's a game-changer
  We measure granular drag force and modify resistive force theory
  To model such dynamics, it's not just a theory
  
  A peculiar gait strategy that agitates and reflows grains
  Allows it to swim up hills, it's not just a game
  Normally substrate disturbance hinders locomotion
  But RP15's multimode design enables effective transport motion
  
  With a diversity of possible gaits, it can self-organize
  Localized frictional fluids that enable it to optimize
  The way it moves through the granular terrain
  Robust and effective, it's a tech that we can't contain.