This sound-sculpture installation has eight individual pieces controlled by a single micro-controller. Each piece uses a solenoid (electro-magnet) to lift an aluminium tube and then drop it onto a Maple wood base causing a percussive sound. Each piece is controlled by its own random electronic circuit with variable probability of operating or not. The time signature is 4:4 and the probabilities of the solenoids operating are varied according to the particular beat of the bar. The result is a kind of rhythmic clatter which is random rather than just being predetermined. There are two PIR (movement detectors) sensors mounted on the wall behind the installation. The work only does anything if someone moves in front of it.