Alright, so I've redrawn the graph from the previous examples just to make a little bit more room and what we've got so far is the original graph and the - a tree version of the graph that we built by search, some kind of data depth-first, breadth-first - any kind of search actually will do, as long as we now have these green edges pointing downward and these red no-tree edges connecting nodes that need to be connected if the edge wasn't actually part of this tree. 