Greenspun's Tenth Rule - Morris's Corollary

Morris's Corollary

Well-known hacker Robert Morris later enounced a corollary which clarifies the set of "sufficiently complicated" programs to which the rule applies:

This can be viewed as a commentary on the difficulty of creating an efficient implementation of the large and complex Common Lisp language, or simply a joke about Lisp's eval function. Both Greenspun's rule and Morris's corollary are examples of a characteristic style of hacker humor known as "ha ha only serious".