I don’t understand what the visualisation screenshot in the README is trying to communicate to me.

Since this is about C declarations: for anyone who (like me) had the misfortune of learning the so-called "spiral rule" in college rather than be taught how declarations in C work, below are some links that explain the "true" philosophy behind C declaration syntax. TL;DR: you declare a variable in C _in exactly the same way you would use it;_ if you know how to use a variable, then you know how to read and write a declaration for it.

https://eigenstate.org/notes/c-decl https://news.ycombinator.com/item?id=12775966 https://news.ycombinator.com/item?id=12775966