A:? The school flag of National Peking University consists of five colors: red, white, yellow, blue and black, which occupy different areas and shapes. Among them, the school flag contains the emblem of Peking University on a white background, which was designed by Mr. Lu Xun. In 1920 Illustration of National Peking University Flag, Mr. Cai Yuanpei explained the meaning of the five colors on the flag of Peking University: red represents "phenomenon science" including physical chemistry and other disciplines. And white is the sum of seven colors of sunlight, "nature is the sum of these three colors", so white is used to represent philosophy; However, "human thirst for knowledge must not be satisfied with comprehensive philosophy and empirical philosophy, but must invade the scope of metaphysics." Black represents metaphysics.