How many kinds of couplets are there?

Spring Festival couplets are classified by use: special couplets for Chinese New Year. Couplets: used in houses, institutions, temples, historical sites and other places. Greeting couplets: used for birthday, marriage, housewarming, having children, opening business and other festive occasions. Elegiac couplet: used to mourn the dead. Give couplets: praise or encourage others to use them. Main hall couplets: couplets hung in conspicuous places in the living room and bedroom to match calligraphy and painting. Word combinations that overlap according to artistic characteristics: the same word appears continuously. Compound word combination: the same word appears discontinuously and repeatedly. Thimble: The bottom word of the previous clause serves as the center word of the next clause. Embedded couplets: including embedded ordinal number, orientation, solar terms, year number, surname, name, place name, name of things (such as medicines), etc. Split couplets: split a combined word into several independent words; Some people divide it into "word segmentation, word combination and word analysis". Phonological association: including homophones, homophones and rhyming words. Humor association: take the meaning of humor. Don't love: the meaning of couplets doesn't matter, but the words are neat. Most loveless couples are interesting and can be classified as humorous associations. Palindrome: read backwards, read backwards, the meaning is exactly the same.