17.12  These four principles of the seasons occur in the "day cycle" too, but of course on a much smaller scale. In this cycle, "midnight" constitutes the principle of winter. "Morning" constitutes the spring of the day cycle, while the day cycle's "noon" constitutes its area of summer. The "evening" of the day cycle constitutes its area of autumn. So here we can also read the seasons of the day cycle in the symbol using the same markings that we have used to symbolise the year cycle.