Here, the piano is used - it could be said - in a metaphorical sense.
In fact, the sound is produced by eight Japanese gongs placed horizontally
above the mechanism of a grand piano and conditioned by the very fast
execution of polyrhythmic figures whose percussive "pianistic"
precision and the variable angle of incidence of the hammers produced
by rotation generate, thanks to the resonance of the gongs, an incessant
iridescent flow of sound tones.