You could do it so it moved in the Y axis to each note location but only plunged if that note should be played. If the note should be played the plunge depth is -1" (or whatever) and if it should not be played the plunge depth is 0". Move down incrementally to the next note position, decide how to plunge, repeat. When you get done with the 20th note position then feed in X (i.e. roll the paper an appropriate distance), move the Y axis to the note 1 location and start over.