The crossword puzzle is a crossword puzzle. You need to guess a four-character idiom according to the description of the crossword puzzle. As the name implies, "Yi Shui Jing" refers to Si Mazhao's generals, while "Lotto Poems" and "crossword puzzles" are the forms of prompting guessing. It can be concluded that the answer is "flowers in the mirror are like water and moon", which is an idiom meaning illusory and unreal.