1. Lighting effect: subway glass has a large area, and combined with the lighting design inside the subway, it has formed a unique lighting effect, which makes the image reflected on the glass have a specific effect, visually stretching the proportion of people's figure and making it more slender.
2. Oval design: The four corners of the subway window are usually oval, which not only improves the aesthetics, but also visually lengthens the height of passengers and makes people look more slender.
3. Reference influence: The glass of the subway is equivalent to a vertical plane mirror. When people look at the image in the glass, they will map their own image into this "mirror". Because the mapping between the environment inside the subway and the proportion of people in the glass is relatively small, people have a "slimming" effect visually.
Generally speaking, the thinness of subway glass is the result of many factors, including lighting effect, oval design and the influence of reference objects.