One day a student came to Moon and said: “I understand how to make a better garbage collector. We must keep a reference count of the pointers to each cons.”

Moon patiently told the student the following story:

One day a student came to Moon and said: “I understand how to make a better garbage collector...

—Danny Hillis explains tale-recursion.

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Q: What's this?

(lambda (x)
  (make-isomorphism x 'howard))

.

A: Gur pheevrq Ubjneq vfbzbecuvfz. (rot 13)