If you want to write a hairpin in lowercase letters, you can also refer to the lowercase letters of Lu Zhongnan, a modern teacher, whose calligraphy works were given to foreign heads of state as a national gift. For example, "300 Song Poems in Lu Zhongnan's Lower Case" is the standard praise case. If you can't reach the level of temporary writing, you can try the method of tracing red. This set of books, Lu Zhongnan's practice copybook in lower case is also good.