d
mirror → b
Four nested layers — context ⊃ electron ⊃ photon ⊃ gluon — the 4D the hypercube added. A david descends through all four to the core, is transcribed, and ascends the other side — mirrored, then inverted. Four crossings in, four out: the eight seams. The exit re-enters as the next input (autoregression), and each pass turns the glyph by one element of the four-group: d → b → p → q → d.