Each stanza has four lines, also called a four-line poem.
A poem with ***four lines in it. This is the most common sentence structure in Chinese poetry. Most of the chapters of a poem in the Book of Songs are four sentences, and most of the Yuefu folk songs in the Han, Wei and Six Dynasties are also four sentences. For example, "Midnight Song" from the Six Dynasties: The setting sun comes out of the front door, and you can see Zidu. The temples are beautiful and colorful, and the fragrance has filled the road. By the time the quatrain became popular in the Tang Dynasty, four sentences were used as the basic structure.