anchor.diff:                            twiddle window window-start
                             ,(gen-dit n :scale  scale
                                         :window (and window-inv 'window)))))
  -         (iota (iota n))
  +         (iota (random-vector n))
            (copy (copy-seq iota)))
       (when window-fwd
         (apply-window-inv copy window))
  
positive.code:               (if fwd "T" "F")
                (if inv "T" "F"))
        (loop for i upto max do
          (format t "~A: ~A~%" i (test-window (ash 1 i)
                                              :window window
                                              :window-fwd fwd
                                              :window-inv inv))))))
  
negative.code:                                    (type index start))
                            twiddle
                            ,(gen-dit n :scale (/ 1d0 n fwd-scale)))))
           (iota (random-vector n))
           (copy (copy-seq iota)))
      (funcall fwd copy 0
               (make-twiddle n))
  