The idea of rotation was carried out in a ceremony described by Molina. When the December moon was full, after having ploughed their fields during twelve days, "all persons returned to Cuzco ... the people went to a house called moro-uco, near the houses of the Sun and took out a very long cable which was kept there, woven in four colors, black, white, red and yellow, at the end of which was a stout ball of red wool. Everyone took hold of it, the men on one side, the women on the other, performing the sacred dance called yaquayra. When they came to the square ... they went round and round until they were in the shape of a spiral shell. Then they dropped the cable on the ground and left it coiled up like a snake. The people returned to their places and those who had charge of the cable took it back to its house." An extremely important instance of the application of the spiral is preserved in an illustration in the Account of the Antiquities of Peru by the native chronicler Salcamayhua (ed. Hakluyt, p. 109). He relates that the Inca Huayna-Capac, when he reached the town of Tumipampa, "ordered water to be brought from a river by boring through a mountain, and making the channel enter the city by curves in this way:"
The illustration, reproduced here (fig. 46), exhibits an extremely ingenious mode of irrigation which divided the country surrounding the town into nine zones of land lying between currents of water. These are cut through by an exit canal which, at the same time, presumably supplied a direct water-way for traffic to and from the town. The association of the spiral form with irrigation would not, perhaps, seem as important and significant did we not know that the ancient Peruvians, as proven by Wiener, habitually laid out the irrigation canals in their maize-fields so as to form regular designs, some of which resembled those illustrated on fig. 40, nos. 2, 4, 6, 7, which have been shown to signify the union of the Above and Below, or Heaven and Earth. In the Peruvian irrigation canals the water supplied the light lines and the earth the dark, and when the small canals were full and were observed in certain lights, they must have resembled light blue or white patterns running through the dark earth. That their inventors and makers actually associated them with profound meaning and laid them from superstitious as well as practical motives is obvious; for, in Peru, as in Mexico, we find the periodical union of the Heaven and Earth, of rain and earth celebrated with ceremonial drinking of chicha, specially brewed for this period which seems to have been the regularly appointed time for juvenile match-making, by order of the Inca.