Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp. https://en.

Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp. https://en.wikipedia.org/wiki/Greenspun%27s_tenth_rule https://en.wikipedia.org/wiki/Greenspun%27s_tenth_rule