Rain on Water is based on the action of ripples from raindrops propagating across a still water surface. The work is a relief sculpture frieze that runs the full 40m width of the central concourse of Butler Train Station. It is consists of 1,200 anodised aluminium rods mounted on a reflective surface. The length of each rod and the colour of its cap are calculated according to a wave propagation and interference algorithm written for the project.