For 10 points, name this composer of some avant-garde Klavierstücke and the Helicopter String Quartet.
One of his piano solos, where the soloist must whisper and make voiceless calls, is an early version of his Lucifer's Dream. Another work contains prayer gestures and was packaged with a Lecture on [the sound] HU, Inori. One scene from his (*) Licht cycle of 7 operas for the days of the week required four of the title objects on loan from the Austrian army. For 10 points, name this composer of some avant-garde Klavierstücke and the Helicopter String Quartet.
One of his piano solos, where the soloist must whisper and make voiceless calls, is an early version of his Lucifer's Dream.
Karlheinz {Stockhausen}