NESTING, NOT STACKING

( (1 2) 0 0 (3 4) )
two paired units · the null doubled into a region, not a point · the outer wrap turns the whole into one object · ready to nest inside the next.
the move
Stacking witnesses gives you three-body forever. Nesting wraps a closed pair as one object — the next level up sees the wrapper, not the pair inside.
why doubled null
One null is a tangent point — three-body again (left + null + right). Two nulls make a region — a no-ack airgap with width. Nothing shared. No third body.
why wrap
The outer ( ) is what lets it nest. Without the wrap, the next level sees four things. With the wrap, the next level sees one.
depth
nesting2
The regress doesn't climb. It encapsulates. Each level hides what's below as a single closed surface — turtles all the way down, but each turtle is opaque to the one above it. That is termination by opacity.