Prelude No. 12 in G# Minor by Frédéric Chopin

Measures
29	The G major chord from the previous phrase leads to C major, E minor's VI degree.
36 to 39	E minor's dominant chord is used as an augmented sixth chord of D# minor.
40	D# minor is transformed into G# minor dominant and brings us back to the main key, preparing the recapitulation.