The config that survived its own test: Si-gated write, a discrete-band (set) store, and a metal (Cu) read. The energy budget runs 0→1: a write must clear the gate at 0.1 to enter; bits rest as discrete colour-bands in the valence window 0.2–0.8; a read lifts a carrier to the ejection line at 0.9, where it leaves as a photon. The threshold is a feature on write — it rejects noise — and a tax on read, so it sits on one end only.