A tower rises 18 m high in front of the north façade of the Palais Liechtenstein, equipped with 108 LED fluorescent tubes, each 1.50 m long, and an 8-channel sound system. What happens with the onset of darkness sets the massive structure in audio-visual motion: following a specially developed score, the tubes light up in a choreographed order and then go out again. The light uses the geometric structure as its scope: it scurries across the surface, dances around the tower, builds it up and makes it disappear again in the darkness of the night. Narrative moments mix with digital aesthetics, generate spatial construction and decomposition. The acoustic composition uses only overtones, those sound components that resonate along with the fundamental frequency of a tone and define timbre. The interplay of light and sound unfolds a fascinating dynamic of moving simplicity.