What are the unparalleled couplets throughout the ages?

1. Smoke locks pond willow: Its structure uses five elements as radicals for five characters; pond is a compound word; the word smoke in the sentence uses a metaphorical rhetorical technique, fog is like smoke; fog hides the pond and willow, and the author uses the word "smoke" to hide the fog in the sentence, thereby depicting a quiet pond, surrounded by green trees and filled with smoke.

2. Lonely and cold, widowed with an empty window: Every word has the same radical, and the meaning is smooth and coherent, as if there is no divine stroke. To this day, no one can figure it out correctly. In fact, it is not because of the exquisite mechanism in the text, but because there is really no context that can match the word "lonely".

3. Draw a lotus and monk painting: This is a palindrome couplet, which is the same whether it is read forward or backward. It is said that this couplet was written by Tang Bohu. At that time, he visited a temple in eastern Sichuan in ancient times. The master in the temple took out a lotus picture and said it was painted by his master, and asked Tang Bohu to write an inscription. Tang Bohu took up the pen and wrote "Painting with lotus and monk painting", and said: "If anyone can match the second couplet, he must be a genius in the world."

Methods for pairing couplets:

1. The number of words should be equal and the sentences should be consistent. Unless the position of a certain word is intentionally left vacant to achieve a certain effect, the number of words in the upper and lower couplets must be the same, no more and no less.

2. The levels and tones must be consistent and the tones must be harmonious. The traditional custom is to use the oblique tone at the end of the first line and the level tone at the end of the second line.

3. The parts of speech should be relative and the positions should be the same. It is generally called virtual to virtual, real to real, that is, noun to noun, verb to verb, adjective to adjective, quantifier to quantifier, adverb to adverb, and the relative words must be in the same position.

4. The content should be relevant and connected from top to bottom. The meanings of the upper and lower lines must be connected to each other, but they cannot be repeated.