Red color indicates the summer solstice. Violet color indicates the winter solstice. Green color indicates both the spring equinox and the autumn equinox. The flow of colors upward the rainbow from violet to red indicates the time from winter solstice to summer solstice. The flow of colors downward the rainbow from red to violet indicates the time from summer solstice to winter solstice.
keywords: sun year, solar year, seasons, yin yang, rainbow colors