Piano Forum

First of all, the overall thing that is going on is that he is on a long pedal point with the dominant, G major, preparing for the return to the tonic of C minor in the recapitulation. In a nutshell that is all that is going on in these bars.

Let's see if it makes sense if you break it down, first into chords on line 2. The dominant of C minor is G major. We often color the dominant with the 7th and even the flattened 9th. If you keep that in mind you can see he's basically got a Gb9 chord with some passing notes, and where the A flat eventually resolves to a G.

On line 3 I have removed the A flat, maybe it makes it clearer. The C#-E are passing notes made from non-chord tones used for decoration. You can see similar ideas in a lot of Mozart. The same goes for the C-Eb (though they fit into the key of c minor). The important notes are the D-F and the B-D over the G pedal, showing the harmony is G7 functioning as the dominant in c minor.

4th line: Funnily enough, the eighth note pattern is just a clever variation on what happens at the end of the ascending quarter note passages in the same part of the piece. See how similar they are?