Could be useful for ephemeral circuitry. When he mentioned printing copper onto glass, I immediately shot to spycraft and having disposable circuitry for clande

Could be useful for ephemeral circuitry. When he mentioned printing copper onto glass, I immediately shot to spycraft and having disposable circuitry for clandestine operatives who could simply smash the glass, breaking the device and making it hard to discern what it was for, even if parts of it were found after the fact.