Speaking of frogs (which are a favourite topic in Zen) there is an article about a species of frog which listens without ears. But if listening without ears weren’t an actual fact this may well have been a koan which would go something like this:
Who is the man who
Speaks without tongue,
Listens without ears,
Sees without eyes?
Getsuan said to his 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.
Getsuan is Rep and Senzaki’s transliteration. Sekida and Yamada call him Gettan.
The Shambhala Dictionary of Buddhism and Zen says Gatsurin or Getsurin. Whichever way you pronounce it it is as irrelevant as the axle being removed in this koan. Remove the axle and the cart is useless or rather the cart has lost its essence. That is the point of the koan though. What is left is Emptiness. But to see that Emptiness as Emptiness that is another thing. That is called Enlightenment, something which I do not have. And all I have shown here, much to my regret, is the ordinary of kind emptiness called intellect or concept.