Others are speculating (if I read it correctly) this might have to do with the originating star being one member of a binary star and the rings associated with how its partner was torn apart in the events leading up to the blast, possibly in stages. That might explain why such a definite orientation to the double intersecting loops of the “figure 8” rather than seeing something symmetrical all the way around.
Could be.There is something called a Stromgren sphere but its only theoretical.Its a region of hot and ionized gas that surrounds a hot center. Of course, the center would be the neutron star.
I think the thin loops only appear to intersect due to our perspective.
To me they look like two thin loops, one on each side of the remnant star, one loop moving toward us, the other away.