This is a modular, immersive, and interactive lighting experience that engages and surprises. When someone breaks the circle of light, it triggers cascading light and sound in the corresponding area of the curtain. When no-one is playing, it provides a gentle audio-visual backdrop to suit the mood or occasion. Lightfall uses a curtain of LED strings that can be adjusted to suit any space. Inside the space, a line of light acts as the main interaction point. A surround loudspeaker array matches the perceived locations of light and sound. Customized software allows smooth and intuitive interaction with people, and other inputs such as audio level and internet application programming interfaces (APIs).