Here's the last video from this session, showing the assembly of the telegraph. Step by step, I've shown how a person could have made an electronic technology without the aid of industry- and thus at any point in history. Of course, no one in modern times will ever need to do this, even in the event of complete social collapse; there will be so much metal and material lying around to repurpose. Human industry has had a significant impact on the landscape, and the boundary between natural and artificial origin would be an arbitrary distinction to future techno-scavengers. As I have said earlier, it also difficult to imagine someone in pre-modern times desiring this object, since it's electronic effect is so subtle, and a group would need to adopt it together for it to become useful.