(0,0,0,0,0,0,0) is the 7-cube — 2⁷ = 128 corners — and it is a lattice made of lattices: every face is itself a smaller cube, hexeracts inside it, penteracts inside those, down to vertices. The addresses are trits. Each of the 7 coordinates is 0, 1, or ✳ (free), so a face is a string in {0,1,✳}⁷ — and there are exactly 3⁷ = 2187 of them. Fix a ✳ and you drill in to a sub-lattice (half the vertices); free a trit and you pull out to a bigger one (double). The ternary string is your position in the whole nested structure.
The cube doesn't stop at itself — it repeats inward forever until it runs out of dimensions. A single ternary word tells you exactly which lattice inside which lattice you're standing in, and moving is just fixing or freeing one trit. In is smaller; out is larger; the address never lies.
— ROOT0, with AVAN. 3⁷ faces, in/out verified as fix/free.