Le Corbusier's later theory and production were largely informed by two important considerations: his idea of "ineffable space" (l'espace indicible), and his singular conception of "acoustics," which he apparently used as a troping or analogical tool in his design method. Le Corbusier was to describe the chapel at Ronchamp (1950-1954), for example, as a building that employed an "acoustic component in the domain of form," and suggested that the project began by taking into account "the acoustic of the landscape." The sources of this cryptic appeal to "acoustics" can be identified with some precision. Its initial possibilities were discovered during Le Corbusier's youthful visit to the Acropolis. During his Purist period the same conceit, now transmuted into a trope of "radiation," was applied to the way works of art interacted with their architectural surroundings. The acoustical analogy, drawing parallels between the emission of sound, light, and psychic energy, was fully established in his competition entry for the League of Nations Headquarters of 1927, a project examined here in some depth. It was in theorizing the role of sculpture in modern architecture-as well as the role of architecture in its landscape setting-that Le Corbusier first came to his paradigmatic trope, which thus finds its origins much further back than his late "synthetic" projects, where it was ultimately to achieve its most effective manifestations.