Possible Clues:

• (Of music) in no key
• Hard-to-hum, in a way
• Like Stravinsky's later works
• Lacking scales, a claw moves on
• An alto in composition lacking an established key
• Like Webern's 'Six Bagatelles'
• Like many Berg or Schoenberg pieces
• Hard to tap one's toe to
• Area with mostly lofty houses working without a key
• Without a key, in music