Inspired by the 2019 Academy Award winning movie “Parasite”, design in aiming to improve the comfort level for lives in semi-basements by improving their nature lighting conditions and special lighting effect in rains, while providing a mutually respectable visual connection with street level. The file was set in a semi-basement dwelling in Seoul, Sounth Korea, where the poor Kim’s family was dwelling in a rather dark, dirty and unpleasant environment. When they look out of the window, they see the filth and garbage of the street; a little light from the side window barely illuminates the room. When sanitation and pest-control was carried out in the street, the spray poured into the room from the tiny window. When it rains, rainwater pouring through the window into the basement rooms. These heartbreaking sense presented the hardships of lives with less privilege and wealth in big cities. In reality, it could intensify the distress lead by social and economic inequality. Due to poverty and high housing prices, the poor in South Korea can only live in the basement or semi-basement, and not only in South Korea, but also in Beijing, Hong Kong, Guangzhou, Shanghai, Shenzhen, etc. The poor condition of basement or semi-basement living space with insufficient natural light and poor ventilation would bring more mental and physical distress to the hardworking “underclass” group. These basic living conditions cannot be guaranteed, and if the drainage facilities are not done well , rainwater will pour into the room on rainy day. The most important thing is that people in the basement have been living in a “look up” attitude, which escalate the disproportional social imbalance , like the repetition in the movie. The indescribable "smell" mentioned-psychologically low value and low self-esteem. Therefore, in order to solve the problem of which portrayed in the movie, we put forward the concept of "periscope" and designed a device that can be installed on the side window of the basement. Through the principle similar to the periscope reflection, the image outside the basement can be converted to a lower The angle of view, and introduce sunlight into the room, so that the semi-basement occupants can see a normal person eye-level street view and natural light they deserve. The device is installed on the side window of the basement, and the modular customization allows the device to be freely disassembled without destroying the existing structure of the basement. With this renovation and installation, the device can be adjusted according to the size of the basement side window, so it is suitable for the space renovation of various basements and semi-basements. The device uses simple and easily available materials and can be mass-produced in the factory, so the cost is low. Economical and applicable, it can be used by the majority of people at the bottom.