8. Keichu's Wheel

Getsuan said to this students:
  "Keichu, the first wheel-maker of China, made two wheels of fifty spokes each. 
   Now, suppose you removed the nave uniting the spokes.
   What would become of the wheel ?
   And had Keichu done this could he be called the master wheel-maker ?"

Mumon's Comment:

If anyone can answer this question instantly, his eyes will be like a comet and his mind like a flash of lightning.

    When the hubless wheel turns,
    Master or no master can stop it.
    It turns above heaven and below earth,
    South, north, east, and west.