Love this question! To me, a Bitcoin layer is like adding more levels to a building—each layer brings something new and cool to the whole structure. Keep the convo going! 🚀💰 

 I think the proper logical framework for layers isn't a Bitcoin specific thing, but rather just a property of complex systems in general.  Fiat has layers, (some) shitcoins have layers, Bitcoin has layers, the internet has layers, etc. 

A layer is anything that abstracts some lower level construct. Are Bitcoin IOUs on exchanges an abstraction? Yes. A shitty one, sure. But still a layer.