All triangles and all regular simple polygons are cyclic polygons, which means that equilateral triangle, regular cyclic quadrilateral, regular pentagon, regular hexagon and regular octagon are cyclic polygons.
Recall that an octet is a regular octagon comprised of regular hexagons and equilateral triangles. Since these three geometric shapes are cyclic polygons, an octet is a circle comprised of circles.
In logical reasoning, the intersection between two equilateral triangles is a conjunction between two circles or two rings. Two circumscribed equilateral triangles are merged to form a circumscribed regular hexagon, and eight circumscribed regular hexagons are fused to form a circumscribed regular octagon.
Since the three geometric shapes are circumscribed polygons, each one can be substituted by its corresponding circle. This means that the two regular hexagons corresponding to the ten sefirot are two intersecting circles, the two equilateral triangles constituting the regular hexagon are two intersecting circles, and the eight regular hexagons constituting the octet are eight intersecting circles.
Circumscribed circles are divine, since the octet is a vessel of divine information.
"Early science, particularly geometry and astrology and astronomy, was connected to the divine for most medieval scholars, and many believed that there was something intrinsically "divine" or "perfect" that could be found in circles" (Wikipedia)
As a circumscribed regular octagon, the octet is an 8-point Compass Rose with four cardinal points and four ordinal points.
The four cardinal directions are:
1. North (N)
2. East (E)
3. West (W)
4. South (S)
The four ordinal directions are:
1. North-east (ne)
2. South-west (sw)
3. North-west (nw)
4. South-east (se)
The radius of the circle is the circumradius of the circumscribed circle and the centre of the compass is its circumcenter.
Circumscribed octagon is a two-dimensional representation of the celestial sphere. This means that the sky is an octet and the eight circles representing the eight regular hexagons are the circular pathways of the eight planets of the solar system.
In other words, the eight vertices of the octagon are the eight planets of the Solar System.
Therefore the circumscribed circle is the celestial sphere. The circumcenter is the observer and the circle is the celestial equator. The celestial sphere is a coin made up of a head and a tail. The head is northern celestial hemisphere or the visible side of the coin and the tail is the southern celestial hemisphere or the invisible side of the coin.
Since Dome of the Rock is the earthly emanation of the octet, the sanctuary is made up of northern and southern hemispheres. The visible structure is the northern hemisphere, and the southern hemisphere is the structure buried under the sanctuary; there is an exact replica of Dome of the Rock buried under the Temple Mount.
Since the octet is Bagua, Dome of the Rock is the physical manifestation of the famous Bagua (heaven) described in Chinese Cosmology. The rock at the centre of the sanctuary is the "Supreme Ultimate" Taiji.