Sphères (2019) is a spatial improvisation where each instrument is electronically live-processed. Starting by introducing a simple idea across the hall, passing between the instruments in a prescribed order, the piece grows into more complex layers as it unfolds and as the ideas start to blur and overlap. The absolute freedom of pitch and rhythm selection is yet bordered by listening to another’s ideas (as it always is in a group improvisation) and matching its sonorities or juxtaposing it with contrasting ones. This piece is designed for the SFCM Concert Hall.