Interesting. I always imagined supply chains as a flow in one direction, with each further step of the chain making more complicated stuff. But your comment mad

Interesting. I always imagined supply chains as a flow in one direction, with each further step of the chain making more complicated stuff. But your comment made me realise that supply chains can be more like a loop, with the more complicated components going back to make the earlier steps more efficient. And a semiconductor factory requires lots of semiconductors themselves. It's like bootstraping a compiler.