http://www.plankman.com/projects/tuned_stairs/

“Tuned Stairs is the introductory installation for the Fabrica exhibition at Center Pompidou on 6 October – 13 November 2006. As visitors walk down the stairs leading to the exhibition, their footsteps activate a musical sound. The installation refocuses the attention of the visitor onto their footfalls – allowing them the opportunity to compose their timing, movement, and the resulting melody […]”

Via: Pixelsumo