sentences:  Thus in the libretto (from the notable expressionist poet and playwright August Stramm) stage directions dominate over speech, which is highly fragmented through ellipses and incomplete phrases.Central to the opera is the expressionistic notion of shock as a means of articulating oneself, and musically, this was achieved to a large extent by pushing harmonic and tonal processes ‘to the very limits of tonality’.Hindemith did not however, divorce himself entirely from formalism, and the work is structured in a series of variations.