 At the Cologne ISCM Festival in 1960 , the Danish composer Per Nørgård heard Stockhausen 's Kontakte as well as pieces by Kagel , Boulez , and Berio . He was profoundly affected by what he heard and his music suddenly changed into " a far more discontinuous and disjunct style , involving elements of strict organization in all parameters , some degree of aleatoricism and controlled improvisation , together with an interest in collage from other musics " ( Anderson 2001 ) . 
