Some poems don't rhyme, but they taste good. For example, since then, love has no good night, let him go down to the west wing in the bright moon. "Mottled shadows hang obliquely on the clear shallow water, and their fragrance spreads peacefully in the moonlight dusk." Until the river bank widens at low tide, and no wind blows my lonely sail.
Metric poetry originated in the Tang Dynasty and is called "modern poetry" to distinguish it from classical poetry. However, in fact, ancient poetry also requires pronunciation, and rhyme is necessary. But why not rhyme? In fact, it is because of the changes in ancient and modern pronunciation.