Experimental big bands began to incorporate elements of free jazz and improvisation as early as the '60s, and fueled by the work of smaller avant-garde ensembles and classical composers, increased their scope in the following decades to embrace atonal music, discordance and increasingly complex structures. From the post-bop beginnings of groups like the Sun Ra Arkestra and Carla Bley's big band, to the full-on chaos of the Little Huey Creative Music Orchestra, experimental big bands produce an amazing diversity of sounds within the large group format.