usually resolves to V/ii and then ii. In this case it does go to V/ii in measure 13.There is a texture change in measure 13. The rythym that was in the bass is now in the treble and is not arpeggios but is a single repeated note figure with an octave jump the second triplet of each beat. The figure in the bass is now eigth note motion with arpeggio implications at the end of each measure. The figure is an inversion of the idea in the treble throughout the past six bars. There is another dramatic change as well. The harmonic rythym has compressed to two harmonic events per measure as opposed to one. This all contributes to more building of tension. The inverted figure, though, serves to provide some unity between this section and the last section. The second harmonic event in measure 13 is a ii chord, as promised by the german 6th (german VI/ii-V/ii-ii). The next measure is iv/ii a g minor chord, followed by an Edim. The Edim tonicizes the F in the next measure, and is therefore viio/IV which moves to IV in the next measure. Here things get more ambiguous. In measure 15, the second harmonic event is unclear. The triplet figure in the treble uses ‘f’ and ‘a’. The bass moves: ‘f’, ‘a’, ‘d’, and then ‘b’ natural in the next measure. The first part of the measure is a clear VI (F). The ‘f’ and ‘a’ seem like an extension of this tonality. The ‘a’ and the ‘d’ considered together seem to reinforce the idea of ii (d) being tonicized throughout the earlier section and suggest that it is still the key center here. The ‘b’ natural (which is part of the ‘f’, ‘a’, ‘d’ eighth note figure) implies that the previous motion has been a kind of arpeggiation of V, the dominant of i or I (which have both been absent for a while). This figure is deliberately obscure and crea...
