anchor.diff:                           (9 6 3))))
         (square= (rotate-square square-1) square-2)) t)
   
  -(rt:deftest mirror-square-horizontally
  +(rt:deftest mirror-square-vertical-axis
       (let ((square-1 #2a ((1 2 3)
                            (4 5 6)
                            (7 8 9)))
             (square-2 #2a ((3 2 1)
                            (6 5 4)
                            (9 8 7))))
  -      (square= (mirror-square square-1) square-2)) t)
  +      (square= (mirror-square square-1 :axis :vertical) square-2)) t)
   
   (rt:deftest normalize-square-1
       (let ((square-1 #2a ((1 4 7)
  
positive.code: (defun range (n)
    "Returns a list with elements 0 to N-1."
    (let (range) (dotimes (i n (nreverse range)) (push i range))))
  
  (defun magic-square-p (square &optional (magic-sum 15))
    "Returns T if the provided SQUARE is a magic square."
  
negative.code:                          (0 0 0))))
        (square= (normalize-square square-1) square-2)) t)
  
  ;;; actual magic squares tests (not just matrix junk)
  
  (defparameter *perfect-square* #2a ((8 1 6)
                                      (3 5 7)
                                      (4 9 2)))
  