Picture of Mary with the twelve zodiac signs (hexagrams) is courtesy of “tpol33” from Flickr who shot it at the Cathedral of Cologne, Germany. The Statue is called Virgo Immaculata and it was made in 1749. This is the first instance of hexagrams representing zodiac signs that I stumbled upon.
It seems like an illustration of Revelation Chapter 12:
1 A great sign appeared in the sky, a woman
2 clothed with the sun, with the moon under her feet, and on her head a crown of twelve stars.