I'm creating a hierarchical tag structure for my portfolio. I have a few top level tags. those could then have children, those children could then have children. Pretty standard so far.
Often a child tag will be under more than one parent (i.e. a child might belong toone or more parents) and it wouldn't necessarily have the same children under one parent as it would in another.
Do and of the current extensions (acts_as_tree, acts_as_nested_set, awesome_nested_set, etc) let a child have more than one parent?