British artist Clive Bell proposed in his book "Art" that "in different works, lines and colors form a certain form or formal relationship in a special way. Stimulate our aesthetic feelings. This relationship and combination of lines and colors, these aesthetic and touching forms, I regard as meaningful forms. Meaningful forms are the unique essence of all art. It refers to the kind of emotion that is different from the beauty of natural objects, but a special, mysterious, and indescribable aesthetic emotion. "Form" is the core of art, and is a kind of composition composed of various parts and qualities within the artwork. A pure relationship means that both meaning and form exist when they exist, and they both perish when they die.