<p><pre><code>    (let ((light t)
          (darkness nil)
          (substrate :land :sea)
          (life &#x27;(:land
                   (:grass :herb :fruit-tree
                           :cattle :creeping-thing)
                   :sea (:fish :dragons :birds)
                   :undecided
                   (:birds :serpents))))
      (defun earth ()
        (let ((total-intelligence 100)
              (reproduction-mode :anisogamous)
              (population &#x27;(1 . 1)))
          (with-mosquitos
           (loop ;; figure out some success condition after lunch
            (collecting (carbon)))))))</code></pre>