The nerd in me does like playing with the typesystem like that.

But I don't see why this
```rust
trait Counter {
    type Output;
    fn get(&mut self) -> Self::Output;
}

struct CartesianDistance { .. }
struct Duration { .. }
```

is better than this:

```rust
trait Timer {
    fn get(&mut self) -> Duration;
}

trait Distance {
    fn get(&mut self) -> CartesianDistance;
}
```