Fomus

(fomus
 :output '(:lilypond :view t)
 :parts
 (list
  (make-part
   :name "Piano"
   :instr :piano
   :events
   (loop
     for off from 0 to 10 by 1/2
     collect (make-note :off off
                        :dur (if (< off 10) 1/2 1)
                        :note (+ 48 (random 25))
                        :marks (case (random 3)
                                 (0 nil)
                                 (1 '(:staccato))
                                 (2 '(:accent))))))))