What does it mean that the green tiles always recall the rain of old times, and the red umbrellas and deep alleys have no old friends?

The meaning of the sentence "The green tiles always remember the rain in the old days, and the red umbrellas in the deep alleys have no old friends" means: when walking in the old alleys, I often think of the rainy days in the past, and hanging out with my friends in the deep alleys. Red Umbrella, but now she is alone. This sentence is not from a poem, but a self-titled couplet. It expresses the author's nostalgia for the past and loneliness.

The first couplet: The green tiles recall the old rain, the red umbrellas are deep in the alleys and there are no old friends

The second couplet: The old white stone cherishes the leisurely spring, and the Wu River and the mountains are old friends.

Rainy days are bound to be accompanied by the appearance of umbrellas. From the original banana leaves, to the oil-paper umbrellas of ancient times, to today’s various umbrellas, our history of rain shelter seems to be as old as our own.

In Dai Wangshu's "Rain Alley", the woman holding an oil-paper umbrella not only touched him, but also touched our heartstrings. But now, on the way to school, the colorful torrent of umbrellas flows everywhere, some go to the library, some go to the East District, and some stay in Zixia. I looked up at my rainbow umbrella. It looked old in many places. Yes, it's been a while.

Under this umbrella, there have been arguments with friends, breakfasts to catch up with classes, and in-depth conversations with teachers... Now there is only the sound of rain falling on the umbrella. I am afraid that the people under the umbrella or those who once held the umbrella with me will never be able to get together again.