Harmony: that is, flat and parallel. The above sentence is straightforward.
The next sentence should be correct: ping ping ping (Chinese pronunciation is flat one or two tones, flat three or four tones)
Rhyme: In other words, the vowel of each last word should be pronounced the same.
Metrics: one to three, hundreds to thousands, heaven, etc. ...
It completely conforms to the format of ancient poetry and is called quatrains. For example:
Two orioles sing green willows, and a row of egrets go up to the sky.
The window contains the autumn snow in Xiling, at the gate of Wu Dong Wan Li boating.
One, two, four sentences rhyme, if there is rhyme, it is metrical poem ... every sentence can rhyme, but it must be in tune.