anchor.diff:        (etypecase pitch
           (integer (note 0 length (et pitch) :cfg (list :env nil :loop nil :duty (random 3) :vol 7)))
           (null (rst length))))
  -    '#1=(9 7 . #1#)
  +    '#1=(6 . #1#)
       notes)))
   
   (defpattern sax-3A (:accompany ((bassline-3A)))
  
positive.code: (nesmus:define-song "Steps" ())
  
  (defpattern bassline-1A ()
    (tri 32 (et  -1) :d 31 :vibrato-delay 12)
    (tri 32 (et  -3) :d 30)
  
    (tri 32 (et  -5) :d 31 :vibrato-delay 8)
    (tri 24 (et  -7) :d 21)
    (tri 24 (et  -9) :d 23)
    (tri 16 (et -10) :d 13)
    (tri 16 (et -12) :d 13)
    (tri 16 (et -14) :d 13)
  
    (tri 16 (et  -3) :d 13)
    (tri 16 (et  -5) :d 15)
    (tri 16 (et  -6) :d 13)
    (tri 16 (et  -3) :d 15))
  
  (defpattern bassline-1B ()
    (tri 32 (et  -5) :d 30 :vibrato-delay 12)
    (tri 32 (et  -7) :d 30)
  
    (tri 32 (et  -9) :d 30 :vibrato-delay 8)
    (tri 24 (et -11) :d 21)
    (tri 24 (et -13) :d 21)
    (tri 16 (et  -6) :d 12)
    (tri 16 (et  -2) :d 12)
    (tri 16 (et  -6) :d 14)
  
    (tri 16 (et  -7) :d 12)
    (tri 16 (et  -5) :d 12)
    (tri 16 (et  -4) :d 12)
    (tri 16 (et  -2) :d 14 :vibrato-delay 0))
  
  (defpattern bassline-1C ()
    (apply 'seq (mapcar (lambda (pitch duration) (tri 16 (et pitch) :d duration))
                        '(-9  -2 -5  -9
                          -3 -10 -8  -7
                          -5  -3 -1  -5
                          -8 -11 -6 -14)
                        '(11 11 11 14  11 11 11 14  11 11 11 14  11 11 11 15))))
  
  (defpattern bassline-1D ()
    (apply 'seq (mapcar (lambda (pitch duration) (tri 16 (et pitch) :d duration))
                        '(-13 -6 -1 -6
                          -7 -5 -3 -2
                          -9 -2 -5 -8
                          -11 -8 -6 -14)
                        '(11 11 11 14  11 11 11 12  11 11 11 14  11 11 11 11))))
  
  (defpattern bassline-seq-1 ()
    (bassline-1A)
  
negative.code: 
  ;;; ------------------------------------------------------------
  
  (defun walking-bassline (notes &key (note-length 12))
    (assert (not (zerop note-length)))
    (apply
     'seq
  