Black holes as bricks, as the name implied, meant using black holes as bricks to construct buildings.
The Spirit Realm was just such a colossal structure built with black holes as its foundational material.
First of all, the Spirit Realm's existence involved a spacetime structure. Put simply, it transformed spacetime into a usable "object."
So... the question was, how could that be done?
If spacetime were compared to a sheet of paper, what conditions had to be met at minimum to fold that sheet into other shapes?
There were two: a force that bent the paper upward, and a force in the opposite direction.
Spacetime was the same. Only two modifying quantities were needed—but did such quantities exist that could bend spacetime?
The answer was yes: gravity and antigravity.
With those two forces, the Spirit Realm had the basis for its construction. Spacetime could be kneaded into any shape like modeling clay.
However, forces for distortion alone were not enough. Arrangements were also needed to sustain those two forces. Spacetime itself could not hold its shape like modeling clay; modeling clay retained its shape because electromagnetic force continually sustained it.
Therefore, if they did not want the altered spacetime structure to disperse after processing was complete, it had to be stabilized—that was, gravity and antigravity had to persist continuously.
What could produce both gravity and antigravity?
That was right: black holes. Since black holes were needed to generate sustained gravity and antigravity, the Spirit Realm's basic construction units were black holes.
Put bluntly, it was an array formed by a pile of black holes arranged in a special layout, much like using diodes to assemble a computer. The Spirit Realm was simply far more complicated than a computer.
Black holes did not merely maintain the Spirit Realm; they were also