If I'm listening correctly Chopin's Black Key Etude is a very good example of rounded binary, possibly with a continuous A section. The piece is characterized by a very fast paced right hand with a slower chordal left hand. The piece is in two-four and the right is comprised of sixteenth note triplets for practically the whole piece. In the beginning a distinct I-IV-I progression is used and the first four measures play the main theme of the A section. It sounds like the first four end in a half cadence. The melodic theme repeats for the next four, with maybe an authentic cadence. These four measures are repeated but the cadence seems to be half instead of authentic. Now, the B section plays for about thirty-two measures. This piece is interesting because the left hang seems to have the melody. The Bsection is slightly different because the melody is more in the right hand. In one measure amidst the sixteeth note triplets you can hear the melody very well, mi-re-do, mi-re-do. The A sectin comes back, but when it repeats it does off to a bunch of cadential stuff. At one point you can hear the left hand playing V-I-V-I-V-I, preparing you for the authentic cadence at the end.
The song is cool, it sounds sort of oriental, probably because it is played on all of the BLACK KEYS. I like the continuous motion of the piece. This piece is slightly decieving because it sounds much harder to play than it really is.