+----+ 
                               /|Edge|\
                              | +----+ |
                              |        |
                              |        |
                +----+    +----+     +----+
                |Edge|----|Core|-----|Core|---------+
                +----+    +----+     +----+         |
                        /  |    \   /   |           |
                  +----+   |     \ /    |           |
                  |Edge|   |      X     |           |
                  +----+   |     / \    |           |
                        \  |    /   \   |           |
                +----+    +----+     +----+         |
                |Edge|----|Core|-----|Core|         |
                +----+    +----+     +----+         |
                            |          |            |
                            |          +------\   +----+
                            |                  ---|Edge|
                            +-----------------/   +----+