Large-scale polyrhythms appear in almost every composition Elliott Carter wrote during the 1980s. The roots of this technique can be found in earlier compositions where Carter deliberately combined different simultaneous speeds not only at the musical surface, but also at a deeper, structural level. In A Mirror on which to dwell (1975), he already uses this compositional tool as a form-generating feature. Through the analysis of three songs from this cycle (Anaphora, Insomnia and O Breath), it is shown how the appearance of structural polyrhythms at the musical surface is meticulously organized through pitch organization, instrumentation and the relation with text. The double function of the polyrhythm – as a surface phenomenon and a background structure – is essential for the understanding of this composition. It also shows the difference with Carter's later use of the same technique in the 1980s, where large-scale or structural polyrhythms are more of a constructional nature and remain invisible in the musical score.