By day, the field of leeks looks like any other. But, as the sun sets, blue and red light, mixed with invisible ultraviolet (UV) radiation, transforms the scene into a multicoloured landscape. This LED light show is not just for effect. For a couple of hours every evening the lights are shone across the 20,000sq metre field in Lelystad in the Netherlands in a bid to make the leeks grow better. In a light installation that brings art and science...