 Birrell describes this Chu creation narrative as a "vivid world picture.It mentions no prime cause, no first creator.From the "formless expanse" the primeval element of misty vapor emerges spontaneously as a creative force, which is organically constructed as a set of binary forces in opposition to each other-upper and lower spheres, darkness and light, Yin and Yang – whose mysterious transformations bring about the ordering of the universe.