ALGORITHMIC CYCLE Spires (electronic, 1956) Three 2-Part Inventions (piano, 1960) Three Pieces (clarinet, 1965) Five Pieces (flute, bassoon, cello, 1966) Towers (chamber ensemble, 1968) Birds (electronics, 1968) Margins (chamber ensemble, 1972) Triplum (flute and piano, 1973) Requiem for Bosque Redondo (brass choir, 1974) 1,000 works (with Emmy) (1980-2003) Cradle Falling (opera, 1985) 5,000 works (with Emmy) (1992) Horizons (orchestra, 1994) Organ Concerto (organ, orchestra, 2000) Endangered Species (chamber ensemble, 2004) From Darkness, Light (with Emily Howell) (two pianos, 2004) 5,000 chorales (with Emmy) (2005) Shadows (with Emily Howell) (disklaviers, 2005) Land of Stone (with Emily Howell) (chamber ensemble, 2007)