This is usually a fairly stylised version of the theme, and usually includes numerous added embellishments and connecting notes.The subsequent variations can number from one up to about twenty, although there are a few fragmentary tunes for which only a ground is known.
However, not all pibrochs will include all or even any of these movements but instead use variations that are deemed to be irregular.
In addition the theme will usually have one of several internal structures for the ordering of its musical phrases.
Pibroch, Piobaireachd or Ceòl Mòr is an art music genre associated primarily with the Scottish Highlands that is characterised by extended compositions with a melodic theme and elaborate formal variations.
Strictly meaning "piping" in Scottish Gaelic, piobaireachd has for some four centuries been music of the Great Highland Bagpipe.
The theme is usually a very simple melody, though few if any pibroch contain the theme in its simplest form.