Parallel Movements, for Four Groups of Instruments

'The Mikrokosmos is a cycle of 153 pieces for piano, written with a didactic purpose (Vol. 1: Z. 125, Vol. 2: Z. 126, Vol. 3: Z. 127, Vol. 4: Z. 128, Vol. 5: Z. 129, Vol. 6: Z. 130). That is, to give piano pieces which can be used from the very beginning, and then going on, it is graded according to difficulties. And the word Mikrokosmos may be interpreted as a series of pieces in many different styles, representing a small world. Or it may be interpreted as "world of the little ones, the children".' (Interview broadcast by WNYC, in early 1945, on a programme entitled Ask the Composer.)
Each part may be performed by four to eight instruments, which are all capable of sustaining a note with identical intensity. The written notes can only be read is treble clef but can be placed anywhere in the register. The composition of the groups of instruments within the individual parts should always be varied both as far as the setting and the proportion of the high, middle and low instruments within one and same part are concerned. The various groups may also consist exclusively of wind or string instruments. It is extremely important to precisely keep the durations and the dynamics. For the duration of a note all factors must remain identical. Accidentals always governonly the note they preceed (even within one bar).