Recording and performing prolifically with many collaborators, Parker was a pivotal figure in the development of European free jazz and free improvisation. He has pioneered or substantially expanded an array of extended techniques. Parker is better known for his later work, which rapidly assimilated the American avant-garde — John Coltrane, Pharoah Sanders, Albert Ayler and others — and forged his own, instantly identifiable style. His music of the 1960s and 1970s involves fluttering, swirling lines that have shape rather than tangible melodic content; sometimes he makes use of pure sound in a manner that recalls Steve Lacy's more radical 1970s recordings or the work of some Association for the Advancement of Creative Musicians (AACM) members. He began to develop methods of rapidly layering harmonics and false notes to create dense contrapuntal weaves; these involved experiments with plastic reeds, circular breathing and rapid tonguing which initially were so intense that he would find blood dripping onto the floor from the saxophone. He also became a member of the big band, the Brotherhood of Breath.[4] Parker has also increasingly become interested in electronics, usually through inviting collaborators such as Phil Wachsmann, Walter Prati, Joel Ryan, Lawrence Casserley or Matthew Wright to process his playing electronically, creating a feedback loop and shifting soundscape.