I am not a teacher.
Professor Paul Fry:
"The principle of the poetic function, however, can be understood then as the metaphorization of what is otherwise metonymic. In other words, if I put together a sentence, what I'm doing is I'm putting words next to each other, and that's what metonymy is. Metonymy is a selection of signs, if you will, that go appropriately next to each other according to the rules of grammar and syntax and according to the rules of logic, right; but also perhaps in the ways in which the rhetorical device of metonymy can be understood. If I say "hut" instead of "house"--I'm using an example actually taken from Jakobson's "aphasia" essay--and if I say, "The hut is small," there is a metonymic relationship implied with houses, shacks, mansions, and other sorts of edifice, but which can only really be resolved, perhaps, by the unfolding of the logic of the sentence as in when I say, "The hut is small." So combinatory processes--borrowing the rhetorical term "metonymy" as "that which is next to each other"--are basically metonymic. The available signs to be selected, on the other hand, on the axis of selection are selected for certain purposes if they are metaphoric. Obviously, if I'm just making a sentence, I'm not selecting signs because they're metaphoric. I select them because they go easily next to each other, either for reasons of grammar or syntax or logic."