This work is conceived as a sequence of various kinds of interaction between the two performers. The form (in a single movement) is organized by means of a game of combination and variation of the different textures and types of action. In terms of pitch, the work might be defined as the progressive deployment of an essentially static harmony, where the different harmonic materials are conceived as the mediating means for an exploration of the intimate and sensitive aspect of the contact with the instrument.
The character of the piece, generally static but, internally, in subtle but constant motion, suggests possible connections to the haiku by the Argentinean writer Juan José Saer, from which the name of the piece was taken :
before the storm.
A single leaf trembles.
 translation by the composer