It is like the increase and decrease of a more or less dense compound along melodic and harmonic lines, its aural surface traversed by a continual, obsessive, obsessional, movement. But there is an altogether different thing as well: a sort of central erosion that first arises as a threat among the bass and is expressed in the trill or wavering of the piano, as if one were about to abandon the key for another or for nothing, tearing the surface, plunging into a ghostly dimension where the dissonances would come only to punctuate the silence.