I can't think of an example where the reference count of a file may not be zero even when it is no longer possible to refer a directory or file. 

The only example that I could find for a general graph directory structure is this:

![example of general graph](https://upload.wikimedia.org/wikipedia/commons/5/50/DC8.png)

*(Node 1 would be the north node, Node 2 would be the node Node 1 is pointing too, and so on and so forth)*

If I wanted to delete Node 1, it should be okay since there is only one reference to it (Node 8).

So my question would be: Could anyone give me an example where the reference count is not zero even if it is no longer possible to refer to that file/directory?

This is for a presentation that I would be presenting tomorrow for class. I tried searching for an answer on the net but they all just say the same thing without giving a concrete example. Or maybe I'm just dumb. :)