My favourite example from the Programming Rust book:

enum RelationshipStatus {
    Single,
    InARelationship,
    ItsComplicated(Option<String>),
    ItsExtremelyComplicated {
        car: DifferentialEquation,
        cdr: EarlyModernistPoem,
    },
}

Surprised it’s not

cdr: Box<RelationshipStatus>,

but maybe I’ve done too much Lisp in my life