fn main()
{
  let     v1 = (1, 2);
  let mut v2 = (3, 4);

  let (mut a,mut b) = v1;
  println!("V1: ({},{})", a, b);
  (a,b) = v2;
  println!("V2: ({},{})", a, b);

  v2 = v1;
  (a,b) = v2;
  println!("V2: ({},{})", a, b);
}