Code shared from the Rust Playground

playground.rs

struct Person {
    x: i32,
    y: i32,
}

struct Camera<'a> {
    person: &'a mut Person,
}

fn main() {
    let mut p1 = Person { x: 0, y: 0 };
    let mut p2 = Person { x: 1, y: 1 };
    let mut c = Camera { person: &mut p1 };
    loop {
        c.person.x += 1;
        c.person.y += 1;
        if c.person.x % 2 == 0 {
            c.person = &mut p1;
        } else {
            c.person = &mut p2;
        }
    }
}