In the above images we see Christ in Majesty within a vesica piscis, ostensibly from a medieval manuscript, and an illuminated page from a copy of Ghazali’s The Alchemy of Happiness.
The vesica piscis is formed from the intersection of two circles with the same radius, where the center of each circle is on the circumference of the other.
As close packing of circles results in a hexagonal tiling, so arranging circles in this manner, center-on-circumference, results in a hexagonally-symmetric pattern of overlapping, adjoining lenses (evident in the well-known Flower of Life pattern). As such, all manifestations of this lenticular archetype in nature are fundamentally hexagonal phenomena. The ratio of height to width is equal to the square root of three, the same as the ratio of distance between opposing edges to edge length in a regular hexagon.