This piece is in the Rondó Form. There is a main subject (tema principal) and three subordinate themes.
So the structure is ABACADA, the A part has always been modified.
I have used the "classical" atonal system described by Schönberg and "friends". The dodecaphonic matrix is this:
Several series are combined to achieve the variation and to create tension and rest (they are not randomly combined, as many people think about atonality). The series are notated in the score.
Rondó.pdf
Rondó.mp3