to whom he sent the score and received a ‘warm letter’ in response. In 1931, Koffler created a version for string orchestra (marked as Op. 9a), which earned a much wider audience, especially since it was presented during the 1933 ISCM Festival in Amsterdam. The two versions are principally the same in terms of music material, with only minor differences resulting from instrumentation. Jerzy Freiheiter claims that ‘the orchestral score can be considered as the final version. Rather than being a transcription, it is a multidimensional implementation of the piano work’s polymorphous concept’ (Muzyka, 7–12 (1936), 86).

The work’s ‘theme’ is a semibreve series (no rhythmic pattern), presented at the start of the cycle, bearing the performance indications of piano and lento rubato. The successive variations are almost always based on one level of series transposition. They are made up of three basic segments, corresponding to the prime, retrograde, and again the prime form of the row, but appearing each time in a different rhythmical, textural and instrumental guise.