Mörby Centrum is a Stockholm subway station on red line 14, with art on its platform. The walls look pale and subdued at first glance, while colored tiles are set into the bedrock. The main effect is optical: from one end of the platform, a wall appears white with a light pink shade; from the other, it appears white and grayish-green. Art guide Marie Andersson says the colors seem to change with the viewer’s position. The wall treatment is light, and the color shift becomes apparent from a different position on the platform.

Artists Gösta Wessel and Karin Ek made the effect by lighting the wall from one side and painting in its shadows, then repeating the process from the other side. Their intention was to make the changing scenery of a journey part of the work, both on the platform and between a starting point and destination. Walk along the platform and compare the walls from either end to see the shift. The station is on the subway’s red line 14.