i’m reading through the infernal colopatiron by s. connolly right now and there’s a chapter (no. 14 i think, on page 71?) on ritual constructs. it details linear gate openings and hexagonal pillar constructs etc. if it’s a circumferential design like a geometric shape (usually with corners), each vertex becomes the focus of either a gateway or a pillar (depending on whether you’re opening a current into the “circle” or if you’re charging an item. elements are often used along with other, more abstract representations. elemental inclusion facilitates balance and harmony.
non-circumferential constructs (like the linear designs) are more of a pathworking or gateworking concept similar to the walking of the gates of the necronomicon. naturally, no “circle” (of whatever shape) exists and each gate is passed through sequentially in a linear fashion. each approach has its own merits but naturally, shapes and their corresponding numerological/sephirothic correlations bring new things to the ritual. again, the tarot serves as a great numerological roadmap and can be seen in practise in the heptameron circle.
hexagons, the number six etc relate to the sixth sephiroth (which is the highest level of conscious creation, later radiating down to the tenth sephiroth or malkuth, the physical realm). the heptameron circle is six feet across, surrounded by three more circles each another foot greater in diameter (6" greater in radius). that makes circles of 6, 7, 8 and 9 feet. beyond the outermost circle of 9 feet (again, the “magical” number 9…) is the tenth “foot”, or the “real world” because it’s outside of the ultimate boundary of the circle. the number 10 relates to malkuth, so the “real world” is also the “physical realm”. when you stand inside the 6 foot circle, you are standing in the sixth sephiroth, eminating out to the tenth. this also relates to the hexagonal ritual construct. when you stand in the middle of the hexagon during the ritual, it resembles the hexagram of the macrocosm with yourself at the centre as the sun;)
just a thought. i’ll get back to you with more references.