Much of Elliott Carter’s music of the past half-century has depended on combinations of different musical characters, defined by expressive qualities, playing modes, pitch language, rhythm and tempo. These different characters are often situated in rhythmic grids, many of which are determined by large-scale long-range polyrhythms. Many of these features have been examined elsewhere, with particular concern to the mechanics of creating the sorts of pitch and rhythmic structures upon which Carter’s musical characters depend. The present essay is less concerned with the mechanics of their creation than with the different kinds of compositional realizations Carter brings to the ways musics of varied characters interact, both with each other and with his underlying metrical grids. Examples are drawn from four compositions to illustrate the flexibility and fluidity of Carter’s invention in the interpretation of his underlying musical designs.