Meaning of the Sky The sky was regarded as God that human beings serve and Heaven that determines the fate of life and death. As Heidegger said, the sky is a place that presents the living conditions of mortals. One day, due to the development of technological civilization, the conditions were considered to be made by the mortals, and the sky was taken away. People now regard the sky as a prop in landscape photography. So, in the same situation as Covid-19, the sky asks people to think about the meaning of existence. Modern Cities and the Sky People who lived in the village before the modern times frequently encountered the sky. Now people are only seeing the sky slightly shining between the tall buildings in urbanization, and the chance to see the sky is gradually fading away. How can you find the sky inside the building, where a person lifts his head and looks up is the floor on which the person upstairs steps? Window and a Borrowed Sky A window is a device that looks out from the inside. On this window, we install a “sky box” that draws the scenery of the sky into the interior so that people can look at the sky again. “Sky Boxes” : Camera Obscura and Diffraction When a light traveling in a straight line passes through a small hole, an image is formed when it hits the wall of the darkroom. This Pin-Hole diffraction principle that enables the camera draws the sky from the “sky box” into the building interior. A Changing window We made a window with a “sky box”. The "sky box" placed on the window showing the outside and ventilating changes. It may show the sky, but at some point, it may turn into a ventilated window, or it may become a canopy to block sunlight. Sky boxes Detail The sky box is a structure that allows light to pass through a small hole to form an image on the ceiling by a reflector. We added a convex lens to a small hole to maximize this principle and make the entire ceiling sky. The sky box is made of wire and pulley and can be unfolded. In the folded state, the “sky box” shows the sky on the interior ceiling, and when the wire is pulled out, it becomes a canopy and becomes a ventilation device. Material The sky box is simple and anyone can easily make it from any material such as polywood.