Each of the interjected notes, applied to separate two notes, in order to suggest a staccato, or to embellish a melody; The application is called gracing; Experienced pipers use different types of gracing; Notation of gracing is often unnecessary, but it can be very helpful in tutors and scores (e.g. for Scottish and Galician band playing); NB: ➺ Scotland (Singling, Doubling, and Tachum), and Ireland (Doubling, and 2nd octave Doubling).