One of my favourite mandalas, enshrining the proportions of the Earth and the Moon to create a beautiful 12- and 28-fold pattern, allowing one to track the cycles of full moons, new moons and eclipses.  This pattern is the ground plan that underlies Stonehenge, Glastonbury Abbey, and the Great Pyramid of Giza, amongst others.

The Mandala is 23.5 inches in diameter (Just under 2ft across).