My sister and an art friend of hers, Normarie, my friend Sharon and I are starting to create collaborative mail art. Here's how we do it. I create 3 identical (as identical as I can) postcards with a minimum of elements. Then I mail one to each of them and they finish the card and mail it back to me. It is very interesting to see how we all create our own versions. Below is the original and our finished cards.
It's lots of fun - try it with a friend!
Original card
My sister's card
Sharon's card
My card