In the early 1950s, Le Corbusier began to search for ways of synthesizing sculpture and architecture by using a dichotomy between a ‘mouth’ as an emitter and an ‘ear’ as a receiver. This dichotomy was closely related to his unique concept of théâtre spontané, which signified the event occurred by contact between a performer as an emitter and an audience as a receiver. He put the dichotomy theory into architectural practices in various ways, and built a series of notable buildings. It was in the Chapel at Ronchamp that Le Corbusier attempted to practice such a dichotomy with voices for the first time. According to the dichotomous thinking, he placed a monumental chapel with concave walls and a topographical object, in this case a ‘pyramid’, facing each other in the given site. When a liturgy was celebrated outside, the concave walls of this chapel filled an important role in diffusing the voices of priests and choirs; the ‘pyramid’ was utilized as seats where one could listen to their voices emitted from the chapel. As a result, these two constructions were connected by the voice transmitting from speakers' mouths to listeners' ears. With the aid of human's activities (speaking and listening), he experimented on an ‘acoustic’ synthèse between the chapel as an emitter and the ‘pyramid’ as a receiver. In the same period, applying such an idea to the Governor's Palace, Le Corbusier undertook an ‘optical’ synthèse by means of the reflecting pools placed in between the Palace and the geometrical hill (observation platform). As he explained in Œuvre complète (vol. 5), the reflections in these pools, which increase the visual information of the building received in the eye, generated a rapport between the monumental building (sculpture as an emitter) and the geometrical hill (architecture as a receiver), while simultaneously maintaining distance between them. This attempt at utilizing a physical phenomenon brought about a reconciliation between distance and rapport, which is a prerequisite for his synthèse. Such an ‘optical’ synthèse was taken over in a different manner by the Convent of La Tourette, in which Le Corbusier and Iannis Xenalis devised an ingenious lighting system: les canons à lumière and les mitrailleuses. Under this system, the sculptural elements of the building gained the ability to emit light toward the cave-like interior space, maximizing the potential to receive the light by using darkness. It was through the medium of light that Le Corbusier attempted to connect sculpture (outside of the building as an emitter) and architecture (inside as a receiver), and accomplished the ‘optical’ synthèse. These practices concerning synthèse were inspired by Le Corbusier’s Taureaux series of paintings. The face of un taureau, composed of heterogeneous objects, provided a clue to reconcile distance with rapport, and it functioned as a model of the synthèse that he had explored throughout the 1930s and the 1940s. Thus, this model allowed him to put into practice the dichotomy theory concerning synthèse. Pushing the dichotomy further, Le Corbusier built the Palace of Assembly. In the assembly hall of this building, the sound-absorbing ‘clouds’, achieving a synthèse with a wall reflecting sound, played a vital role in communication with others which he called des inconnus. This unit of ‘cloud’ and wall, ‘receiving and giving’ information like a ‘hand’, functioned as infrastructure to send something unpredictable to des inconnus.