In the sentence, "moss" and "mangrove", "in the rain" and "in the moon", "sparse" and "sad" are wrong with each other, and the latter two groups are self-correcting, which makes the poem have a circular beauty.
It seems unlikely that In the Rain and Mid-Moon will appear on the same night. But when the poet faces one of these pictures, he might as well see another picture he has experienced before.
In this way, the real scene in front of us is intertwined with the scenery in memory, which invisibly extends the connotation of time, suggesting that it is not just one night to stay awake at night and miss people far away.
Let the original impossible artistic conception, only these characters show incisively and vividly, which is amazing.