"Δ / l (Change In Light)" is a series of optical theremins that render natural light into sine waves during each sunset. Every evening, the sound gradually evolves from a loud, high frequency chord when the sunlight hits the theremins directly, to a quiet, sputtering low frequency chord as daylight diminishes. At Wave Farm, Hollander developed the installation into a modular system that can be applied to any space, effectively creating a flexible electronic instrument that “plays" the emergent product of an architectural space and the passing of time through natural changing light. Hollander experimented with approximately 30 optical theremins on-site and explored the variations that result from different spatial arrangements and how they changed the nature of the space.