A sketch: I generate noise and define a list of intervals (or pitches) that is applied to the noise pitches. Whenever one of these intervals (or pitches) is detected, its dynamic is changed to fff. This creates a form of articulation that is determined by the intervallic structure.

(setf intervals  '(-2 -1 1 2 5 -5))


(setf seq
 (loop repeat 200
       with alist = (filter-repeat 1 (vector-to-pitch '(a3 g5) (gen-noise  300)))
       with cnt = 0 
         
       when (memberp (car (pitch-to-interval (list (nth cnt alist)
                                             (nth  (1+ cnt) alist))))
                     intervals)

         append (make-omn :pitch (list (nth cnt alist)
                                       (nth  (1+ cnt) alist))
                          :length '(1/16 1/16)
                          :velocity '(fff fff))
         and do (incf cnt 1)
         

       else append (make-omn :pitch (list (nth cnt alist))
                             :length '(1/16)
                             :velocity '(ppp))
         
       do (incf cnt)))


(omn-list-plot seq :join-points t)

Example with pitches (not intervals)

(progn 
(setf pitches (make-scale 'c4 12))

(setf seq
      (loop repeat 300
            with alist = (filter-repeat 1 (vector-to-pitch '(c4 c5) (gen-noise  400)))
            for cnt = 0 then (incf cnt)
            with cnt2 = 0 
              
            when (= (pitch-to-midi (nth cnt alist))
                    (pitch-to-midi (nth cnt2 pitches)))
                
              append (make-omn :pitch (list (nth cnt alist))
                               :length '(1/16)
                               :velocity '(fff))

              and do (incf cnt2)

              
            when (= cnt2 (length pitches))
              do (setf cnt2 0)
              
            else append (make-omn :pitch (list (nth cnt alist))
                                  :length '(1/16)
                                  :velocity '(p)))))


(omn-list-plot seq :join-points t)