Gnomon is a group of sound-producing bodies, each whose form and resonance are determined by an audio feedback loop. The sound producing element in each body is a thin metal wire that contracts and relaxes in proportion to the amount of signal passing through it. This wire holds a bronze sheet in tension and is connected to the speaker terminals of an audio amplifier. The amplifier receives its input from a contact microphone placed on the sheet, and a magnet placed under the wire makes it vibrate audibly when an audio signal is passed through the wire.

This system constitutes a feedback loop that dynamically determines the shape, motion and sound the bronze sheet produces. However, environmental variations such as temperature, humidity, air currents and ambient sound serve to disrupt this stability, producing changes over time.

Each sound body is approximately 24" x 6" and is suspended from the ceiling. Installation can include from as little as one body to as many as there are audio input/output channels. Gnomon has currently been redesigned to be powered not only by the grid, but also solar panels, and has appeared in Solar One's CitySol 2007 festival.