Like bronze: alloy copper & tin together, when tin only came from a very few places on earth.

Linen is my usual example of cultural encoding of what we now see as early tech. Making linen from flax is complicated.

https://magiclinen.com/blogs/blog/how-is-linen-made

Ridiculously complicated. And there were oral folk tales passed along for years to keep the cultural memory of it.

Eventually Hans Christian Andersen and the Brothers Grimm wrote their versions down.

Andersen: https://fairytalez.com/flax/

Grimm: https://etc.usf.edu/lit2go/175/grimms-fairy-tales/3081/mothe...

There were cultures thousands of miles apart with their own linen stories and games that all encode linen processing. There are more than these if you look for them:

https://ltfai.org/app/uploads/2021/03/Flax-journey.pdf

https://folklorefairytales.wordpress.com/2012/09/16/the-disc...

I read only Grimm'd story, and there's no linenmaking in it?

Take, for example, Clovis points (https://en.wikipedia.org/wiki/Clovis_point). There is an amazing amount of skill in those relatively utilitarian tools.

How did they cut their nails, I always wonder.

Like, by the time you have metal you can have scissors, but when you’re still working with flint that’s not really an option.

Bite them, tear them or wear them down with manual tasks I imagine.

Flint could make a blade sharp enough to carefully carve your nails back if you really wanted

If you're careful you can bite a spot and then use a different nail to break the longer part without much hassle It's a lot less destructive to the teeth and has the bonus of smoothing the nail

Rough stones are easy enough to find if they needed to file them but if you've ever seen the hands of someone who does a variety of hard manual work every day it's more likely their nails were just worn and broken naturally with the odd bit chewed off.

> How did they cut their nails

They didn't. Probably like felids don't cut their claws.

No need to cut them if you occasionally idly rub a rough rock against them, filing them down before they can get long.