**several things**

- same vertex count ` = (v0...v19)`
- edge list has same vertex indices to build each edge `= [[v0,v1],...[v10,v11],[v18,v19]]`
- same vertices build the polygon list `= [[v14,v15,v7,v4],...[v7,v6,v18,v19]]`


![enter image description here][1]
![enter image description here][2]


  [1]: https://i.sstatic.net/BVUqn.png
  [2]: https://i.sstatic.net/2koHX.png