In Rust, one way I use shadowing is to gather a bunch of examples into one function, but you can copy and paste any single example and it would work.

    fn do_demo() {
        let qr = QrCode::encode_text("foobar");
        print_qr(qr);
        
        let qr = QrCode::encode_text("1234", Ecc::LOW);
        print_qr(qr);
        
        let qr = QrCode::encode_text("the quick brown fox");
        print_qr(qr);
    }

In other languages that don't allow shadowing (e.g. C, Java), the first example would declare the variable and be syntactically correct to copy out, but the subsequent examples would cause a syntax error when copied out.