Help with Swap Practice

So I have 4 objects, how do i make them change places?

I'm looking for a method that allows me to make them swap places with a click, or a keystroke, not randomly, but in the order that i choose them to.

I'm thinking that maybe a list could work, but i'm not sure on the code that I should use. Basically, i want to know how do i swap, for example the object on position 1 to the position 4, and that the object in position 4 moves to the position 1. And so on...

[dubastot]

Drop a dummy at each of your objects. Just have a method where when mouse is clicked on this object move to that object's dummy.