Imagine a circle with a single twist. Imagine taking hold and moving the circle in the manner of a conveyor belt. From a fixed view point the belt appears to be moving forward and backward in perfectly equal measure. Now twist the circle a couple more times. The spirals become more visually pronounced and the conveyor belt continues to operate in the same manner. Where is the beginning? Where is the end?
Shingon Mikkyo has a term "Nyuga Ganyu," "entering into, being entered into." The above image is a pretty good visual description of Nyuga Ganyu. From one perspective the balance is absolute. It is singular. (The circle) From another perspective it is relative "+ & -" "entering into, being entered into" "in/yo, yin/yang".
From the absolute perspective time makes little sense. From a relative perspective time makes sense (past/future) and a spiral can appear proceeding and receding in equal measure.
From here all hell breaks loose!
In Shingon, there is also a Heaven/Earth/Man conception as well. Probably the easiest place to see that is in the floral arrangements of the Sagago Ryu school of Ikebana.
All over simplified and FWIW. (How does one over simplify a singularity?)
Very cool BTW. I don't recall this from my trips to Aizu. Thanks for posting and for the YouTube link.