User can create older versions of targets

Pros:
-user can keep mind the same if needed
-user choses time gap
-version disappears after 1 hour
-user can control version

Cons:
-user can't always change mind of version
-version is like a ghost to objects in present
-anything done by version is erased when it leaves
-user doesn't have full control

Weakness: overuse
User sees own future with overuse