Iterator Chain

fn main() {

    let numbers = vec![1, 2, 3, 4, 5, 6];

    let sum_of_squares: i32 = numbers

        .iter()

        .filter(|&&x| x % 2 == 0)

        .map(|&x| x * x)

        .sum();

    println!("sum of even squares: {}", sum_of_squares);

}