Much of the wisdom of Common Lisp has been lost and left to be rediscovered by new generations of programmers. The following "rules" have not been lost to time, though.
- Greenspun's Tenth Rule: Any sufficiently complicated C or Fortran program contains an ad hoc informally-specified bug-ridden slow implementation of half of Common Lisp.
- Strandh's Thirteenth Rule: There is no limit to the time nor energy that many programmers are willing to spend to avoid learning Common Lisp.
- Burton's Eighteenth Rule: Every Lisp programmer will be tempted to create their own iteration facilty that has neligible new features and immeasurable new flaws when compared to Common Lisp's LOOP.