When you design a building, how do you approach its relationship to the urban context? Architecture that does not interact with its surroundings does only half of the job. Case study: N-House Sou Fujimoto, development of new lighting system that concerns also the facade. The facade of the buildind is designed to reflect the urban context during the day while during the night, thanks to the ligting system, reveals what is inside. Special designed curtains, painted with photochromic paint, are activated by the light. Every curtains has different colours. By placing the coloured curtains close to the holes the architecture will appear as a coloured glowing lantern during the night.