Well, from a computer's point of vue they probably are not :-)

But from a user's perspective it can get confusing. Consider this use case :

I start a new drawing and title it "school trip meeting".
It quickly fills up so I need to exit and start another. And another. And another.
Then I have to exit, go to graffiti wall, and edit a previous one because something I scribbled there has been added to or corrected. From there I can navigate between scribbles with the arrows to edit them too, which is convenient. But after a while of this there seems to be no logical order in which the 10+ "slides" appear...

Does this make sense ? Or am I just using it wrong ?