Maybe just as important is the fact that Zorn's side project Naked City is generally regarded as an important avant-rock/jazz outfit, and his Painkiller project takes things to even greater extremes with a mix of grindcore and free jazz. Not only has he repeatedly joined forces with Fred Frith (Henry Cow, Art Bears), he has also collaborated on several occasions with Mike Patton (Mr. Although very few people would think of John Zorn as a progressive rock artist, his close relation to the genre can't be denied.