anchor.diff:  
   (defun write-pulse (o len)
     (princ (code-char len) o))
  +
  +(defun write-gap (o)
  +  (format t "Making empty gap...~%")
  +  (write-pulse o 0)
  +  (write-pulse o #x7a)
  +  (write-pulse o #xfb)
  +  (write-pulse o #x05))
   
   (defun write-short (o)
     (write-pulse o +short+))
  
positive.code:       (= x (>> x 1)))
      (write-bit o chk)))
  
  (defun write-leader (o)
    (format t "Making leader...~%")
    (adotimes #x6400
      (write-short o)))
  
  (defun write-trailer (o)
  
negative.code: 
  (defvar *chk* 0)
  
  (defun write-byte-without-checksumming (o x)
    (write-sod o)
    (let chk 1
      (dotimes (i 8)
  