Lighting Limit （Even if Chinguetti is gradually swallowed up by the sand, I will remain here to fulfill my mission.）The ancient city of Chinguetti in the Sahara Desert is facing the pain of its aggression and expansion by sandstorms. The ancient city was swallowed three times by the desert three times and rebuilt three times.The most precious library in the ancient city is gradually being buried by the sand. This ancient city is about to be swallowed by the sand.Many people give up their spiritual homes to move from here, only a few guardians of the spiritual civilization of the library remain here to protect this pure land of human civilization. In order to save this ancient human spiritual civilization and the valuable libraries can be found and retain their functions, we will use five libraries as the entrances of the village and connect them with "light barrier" to protect the whole village. Sunlight is constantly reflected to the library through the curved entrance. People pass through the entrance to the civilized country behind the barrier, from the endless desert to an oasis of civilization. With human civilization to resist the desert.The sand is collected and piled up in different stages to form the entrance passages. The acrylic panels at the entrances are bent so that the light is constantly reflected into the dim library to guide people there.Using the sacred status of the library guides the residents here to clean the entrance. The entrance system of the library, as a symbol of academic spirit, not only guards the whole town, but also provides the direction for pedestrians in the desert to purify the spirit and motivate them to acquire knowledge. The main structure of the entrance is acrylic plate, reflective film structure and mineral salts.People process the local rich mineral salt and simply cut them to take on different shapes. They are then packed into translucent acrylic hollow walls that are layered through partitions to allow the mineral salt to be fully exposed to the sun. During the day, the strong sunlight from the desert shines on the ore blocks, diffusing through their natural texture and irregular cracks, and refracting again through the acrylic plate, forming a barrier of light. We added a film structure that can strongly reflect the light outside the acrylic structure on the surface of the entrance. First, the raw material is melted into a glass liquid at a very high temperature. The glass liquid passes through a special nozzle to form many mist-like droplets. These droplets automatically form a regular spherical shape under the action of surface tension, and then undergo certain treatment after cooling. You get very useful glass beads. This material combines with the light refracted by the local salt crystal ore to form a very bright light barrier. A material with reflectance in between these two extremes is called glossy or shiny. The gloss is responsible for the lustrous appearance of the lighting films. Even if the library is finally swallowed up by the desert and sleep underground, the earth flickering light will become the mark of the human once guard civilization.