The intervals of the perfect fifth and semitone (more generally, IC 5 and 1) are a central focus in Ruggles's late music, but little investigation has been done on how he used such spare materials to create large passages of music. A 1940 letter from Ruggles to John Kirkpatrick sheds light on this process. In the letter, Ruggles writes out a 7/1 combination cycle and two "unfoldings", each realizing the model in rather different ways. Taking this letter as a starting point, I explore: (1) properties of Ruggles's model; (2) how it serves--and does not serve-as the basis for his two unfoldings through alteration, rearrangement, and elaboration; and (3) how these and other strategies for combining IC 5 and 1 are implemented in some of Ruggles's later published and unpublished works, specifically the unpublished Visions (realized by John Kirkpatrick) and Evocations 4.