What is the technique used in the seven-step poem?

Cao Zhi used the rhetorical devices of "metaphor" and "personification" in his seven-step poems, giving out the feeling that "brothers are killing each other". 1. Metaphor: Two brothers kill each other. The author expresses Cao Zhi's complex mood by metaphor. For example: beans and beanstalks are born from the same root, metaphorically (Cao Zhi and Cao Pi brothers); The beanstalk burning under the pot is compared to the man's brother Cao Pi; The beans in the pot are metaphors of the poet himself. This article expresses the poet's sadness. 2. personification: the bean is dead and I don't know how to cry. Modern poets give it humanity, making it look alive, able to feel and know how to cry.