anchor.diff:    (iterate (for-nested ((i :from 0 :to 999)
                           (j :from 0 :to 999)))
              (for product = (* i j))
  -           (when (palindromep product)
  +           (when (definitely-palindrome-p product)
                (maximize product))))
   
   (defun problem-5 ()
  
positive.code:     (iterate (for i :in (primes-below 1000000))
               (counting (circular-prime-p i)))))
  
  
  ;;;; Tests --------------------------------------------------------------------
  (def-suite :euler)
  
negative.code:            (finally (return result))))
  
  
  (defun palindromep (n &optional (radix 10))
    "Return whether `n` is a palindrome in base `radix`."
    (let ((s (format nil "~VR" radix n)))
      (string= s (reverse s))))
  
  
  (defun sum (sequence &key key)
  