The sun also a constant..........the symbol of the SI of Dc......

Floor

The marble floor of the Great Hall contains a number of modeled and incised brass inlays. The center represents the Sun, on which are noted the four cardinal points of the compass, indicating the main axes of the building. A decorative scale pattern encloses the Sun with alternate sections of red and yellow Italian marble, the former from Verona and the latter from Sienna.
Twelve squares at the perimeter of the floor of the Great Hall represent the signs of the zodiac. The other squares form two patterns of rosettes. They are embedded in blocks of dark red, richly mottled French marble, with borders of pure white Italian marble.
Proceeding clockwise from bottom left, the zodiac signs are Leo, Cancer, Gemini, Taurus, Aries, Pisces, Aquarius, Capricorn, Sagittarius, Scorpio, Libra, and Virgo.