ALTHOUGH this mandala appears as a fantastical bejewelled Celtic brooch, fit for Guinevere’s robe, or a design to be wrought in the most precious of metals and gemstones on King Arthur’s shield, it is more than an elegant amassing of rubies, sapphires, emeralds and gold. Its four-square design equates it with the natural world of the four elements, the four points of the compass, the four seasons, the four ancient humours.