What is the rhetoric of the hole in the chin?

Metaphor, personification and exaggeration are all used.

Selected Stories of Parent-child Reading: A Hole in the Chin, edited by Mei, a famous children's literature writer and professor of Shanghai Normal University, has selected fairy tales, stories, essays and poems suitable for children aged 2-6, including the classic works of many children's literature writers at home and abroad. I hope parents and teachers can read pure children's literature works with their own voices and words, share stories with their children wholeheartedly, travel to the story country hand in hand with their children, and have a happy time full of warm language.