This piece is an example of simple ternary form. The A section begins in the key of Bb Major and consists of two phrases and a developmental section. The first phrase is four measures long and ends on a PAC in the original key of Bb Major. The second phrase is also four measures long and ends on a PAC, but in the dominant key of F Major. I consider the next eight measures to be a developmental section of the A section motive. The rhythm and harmonies vary from the original motive, and there are several shifts in tonality. All of the above examples of structural phenomena serve the purpose of developing the original motive. The first four measures end on an IAC in C Major, and the second four measures end on a PAC in the original key of Bb Major. The fact that the A section is closed allows the B section to be independent. The A section briefly returns. but only for two measures, and then the B section begins.
The B section is easily differentiated from the A section by an immediate shift in tonality from Bb Major to G Major, a change in rhythm in the motive, and the accompaniment style is different. At the end of four bars, there is a HC. We then have the brief shift to Eb Major... ok kids... what is that? Can we say chromatic mediant?!?! Anyway...the Eb chord is also the dominant chord in Bb Major, our original key, and makes for a lovely pivot back to the A section. And there we have it. Maybe crazy Bob Schumann should've taken it easy on the NCT's.... yeeeeshh this was hard to analyze!!