The collaborative poetry project Borrowings investigates and theorises some of the processes of poetic composition. Two collaborators, by making use of incepts from each other's work, have generated new poems by exploring the nature of intertextual genesis. This paper presents key ideas generated by this activity and, in doing so, applies Deleuze's analysis of games to its consideration of the nature of poetic composition, along with his contention that [t]o pass to the other side of the mirror is to pass from the relation of denotation to the relation of expression. It is to reach a region where language no longer has any relation to that which it denotes. The project explores some of the ways in which poetry makes sense, both to the writer and reader; as well as questioning the extent to which poetry depends on its author's decision about what to write. It also teases out some of the implications for how we understand authorship if authorial decisions may be generated by incepts of one kind or another that occur to the poet apparently randomly, or may be given to them by a line or phrase that they encounter while reading. This paper's ultimate wager, and one put to the test in the project itself, is that limitation has an expansive effect on the generation of creative work.