Mountains

for three or more voices

by Joseph Zitt

Someone sings the beginning of a syllable
  at any pitch
  at any volume
  starting with 
    any consonant or combination of consonants
    followed by a sustained vowel sound.
                      

If you are singing,
  you may end your syllable at any time.
  If someone else is singing,
    do not change from the vowel
      that you have been singing.
  If no one else is singing, 
    you may end your syllable
      with any consonant or consonants.

If you are not singing,
  If someone else is singing,
    If you were the last person to start singing,
      do not start singing again
        until at least one other person 
          has started singing 
          or until after a silence.
    If you were not the last person 
      to start singing,
      you may begin singing any syllable
        on any note that sounds appropriate
        with the notes already sounding.
  If no one else is singing,
    If you were the last person to stop singing,
      do not start singing again
        until at least one other person 
          has started singing.
    If you were not the last person 
      to stop singing,
      you may start singing 
        any syllable 
        on any note,
        after the silence has lasted at least
          as long as the average length
            of the sounds and silences 
              that preceded it.
                      

The piece ends
  after a predetermined duration
  after a predetermined number 
    of sounds and silences
  at an agreed signal
  or by consensus.