This is a light installation which was developed during a residency with the Glynn Vivian Museum in Swansea and now completed for Galeri in Caernarfon. It exploits the unexpected optical properties of the commercially produced pvc strips. A screen of pvc strips divides the room and two coloured lights move up and down to cast coloured shadows on the opposite wall. The pvc alternates clear with opaque strips and the pattern in the colour comes from imperfections in the clear strips. While the red light casts red light through the clear strips, it also casts a complementary coloured shadow next to it. Simultaneously, the green light casts both a green light and a red shadow. The green and red projections coincide with their neighbour's complementary shadow to reinforce the colour. The difference is reinforced by the columns of light moving in opposite directions.