After I was comfortable enough in Rust to start writing reasonable projects, I soon encountered modules as a necessary subject, and it confused me so much. I decided to take a couple hours to read docs, play around with some drop-dead simple code that would organize code into modules as either `mod foo { }` blocks, single file modules (foo.rs) or modules with their own submodules, organized by directory (foo/mod.rs with foo/bar.rs).

It pretty much instantly became obvious how to use them, and in retrospect, I don't know why it was so confusing. I think it's a good example of how important it is to [a] apply deliberate practice/learning and [b] have empathy for others that haven't (yet) progressed to our own level of understanding.