anchor.diff:        (write-byte average out))
       (awhile (read-byte in)
               nil
  -      (write-byte (+ shortest (bit-xor (>> ! 4) 8)) out)
  -      (write-byte (+ shortest (bit-xor (bit-and ! 15) 8)) out))
  +      (write-byte (number+ shortest (bit-xor (>> ! 4) 8)) out)
  +      (write-byte (number+ shortest (bit-xor (bit-and ! 15) 8)) out))
       (adotimes pause-after
         (write-byte average out))))
   
  
positive.code:     :pty cl:*standard-output*))
  
  (defun unclip (x range)
    (integer (+ (half (- 16 range)) (* (/ x 16) range))))
  
  (defun nipkow-average-pulse ()
    (integer (/ (cpu-cycles *tv*) *nipkow-pulse-rate* 8)))
  
negative.code:     (awhile (read-word in)
              nil
        (let sample (bit-xor (>> (unclip ! *bandwidth*) 12) 8)
          (write-byte (number+ shortest sample) out))
        (& *video?*
           (read-byte video)
          (write-byte video out)))
  