anchor.diff:                (dest-map (make-array (list dest-width dest-height) :initial-element -1)))
             (dotimes (x0 src-width)
               (dotimes (y0 src-height)
  -              (let* ((x1 (mod (1+ x0) src-width))
  -                     (y1 (mod (1+ y0) src-height))
  +              (let* ((x1 (mod (1+ x0) (1+ src-width)))
  +                     (y1 (mod (1+ y0) (1+ src-height)))
                        (dest-x (mod (ceiling (* x0 diff-x)) dest-width))
                        (dest-y (mod (ceiling (* y0 diff-y)) dest-height))
                        (current (aref map x0 y0))
  
positive.code:     (blend-maps small medium big)))
  
  (defun resize-map (map dest-width dest-height)
    (let ((src-width (first (array-dimensions map)))
          (src-height (second (array-dimensions map))))
      (if (and (= src-width dest-width) (= src-height dest-height))
          map
          (let ((diff-x (/ dest-width src-width))
  
negative.code:           dest-map))))
  
  (defun gen-whitenoise (width height)
    (let ((width (1+ width))
          (height (1+ height)))
      (let ((noise (make-array (list width height) :initial-element 0)))
        (dotimes (x width)
          (dotimes (y height)
            (setf (aref noise x y) (random 256))))
        noise)))
  
  (defun gen-smooth-noise (base-noise octave)
    (let* ((dimensions (array-dimensions base-noise))
  