In Rust: what is the difference between self and Self (lowercase and uppercase)?

Hi everyone! I started learning Rust and came across a strange thing: in code I often see `self` and `Self`, but they are used differently. I'm confused. Here is an example from the Rust book that I'm trying to understand: ```rust struct Point { x: f64, y: f64, } impl Point { fn new(x: f64, y: f64) -> Self { Self { x, y } } fn distance(&self, other: &Self) -> f64 { let dx = self.x - other.x; let dy = self.y - other.y; (dx * dx + dy * dy).sqrt() } } ``` I see that in `fn new` it returns `Self`, and in `fn distance` the parameter `other` has type `&Self`. Inside the methods I access fields via `self.x`. But aren't `self` and `Self` the same thing? Why are they written differently? My question: what is the fundamental difference?