You can listen to Judith Ortiz Cofer as she gives the assignment.
Listen to the audio.
" . . . the exercise that I would like for you to consider is: given an incident in your lives or an event that you find unforgettable-for me, it was the six months when we didn't know whether my father was alive or dead and I had to learn English for the survival of my family, and I've written about it and written about it again. Given an incident, I would like for you to do a little paragraph or the beginning of a poem or a cast of characters and tell me why you would choose to write in the genre that you chose or whether you would choose to mingle it. For example, you can choose to do it as a news flash or you can choose to start it lyrically or you can choose to do like the . . . describe an incident like a surgery in lyrical terms. But what I would like is for you to be able to tell me why the subject seemed to demand that form and how you would ask your students to switch genres or to feel free to let the theme call forth the genre needed."