What's the function of the problem of warm snow?

It can be seen from the snow that it means cold, but the word "warm" describes an opposite contradiction, that is, the warmth of snow is the main bright spot, and it should be a caring and warm person or thing that appears in the indifference of human nature. The application of foil technique can highlight the theme, or render it vivid and give people a deep feeling. Foil can be divided into positive contrast and negative contrast. As the saying goes, "Although peony is good, it should be supported by green leaves. Matching things A and B is a foil. Things B are clearer, more vivid, more prominent and easier to understand because of things A.