Historically
In 1990, in group work over J-C. Bélanger's composition (ex: "Y'en a qui font de la musique"), we first noted the intuitive pattern where a musical piece changes the size of its basic phrasing Level 0, usually at its most important inner breath, invariably at the next smaller level, typically for the rest of the song, also carried rhythmical constraints that where easy to miss and had often been missed, with odd results. Still, it took 5 to 10 years to start applying the pattern to common popular and folkloric repertoire analysis (ex: "Joy to the world" and "J'ai du bon tabac"), optimizing structure and harmonization.

From Large To Small

The change is invariably made to the next smaller level,
     which confers 2 advantages -
          1. the "tightness" of the fit at the change, and
          2. the increased level of activity at the second, smaller level.

Joy To The World

This song has already received considerable attention
     and there seems no point in analyzing it here
          when it has been done at length in Analysis.
The important thing here is to identify it as one of the few cases
     of evident Level 0 Change.

J'ai du bon tabac

The Level 0 Change is at a much smaller level in this song, so small in fact, that the whole process is repeated within the song, once in the A section, with its Feminine Rhyme, and once in the A' section with its Masculine Rhyme, with only 1 Level 0 cell before the Change, rather than 2 cells as in the previous examples.

The first large Level 0 cell is composed of the first 5 notes, /
     and the 2 small Level 0 cells are composed of the next 6 notes, / / ()
          with the longer Beat to return to the larger Level 0 (or to end).

Change As Bridge

La Raspa has a chord pattern of M5324 3434 5324 in which the Level 0 Change acts as a Bridge, in contradiction to the general principal that a Bridge should preferably be at a larger level.

This form of Level 0 Change should not be confused
     with the other examples of this page
          which close after the lower level section.