+-------+   +----------------+       +----------------+   +-------+
 |+-----+|   |+--------------+|       |+--------------+|   |+-----+|
 ||  CE ||   ||     PE       ||  ...  ||       PE     ||   || CE  ||
 |+--+--+|   |+---+--------+-+|       |+-+--------+---+|   |+--+--+|
 |   |   |   |    |        |  |       |  |        |    |   |   |   |
 |+--+--+|   |+---+-----+  .  |       |  .  +-----+---+|   |+--+--+|
 || MEP ||   ||   | Up ^|  .  |  ...  |  .  | Up ^|   ||   || MEP ||
 ||DownV||   ||MIP|MEP  |  .  |       |  .  |MEP  |MIP||   ||DownV||
 |+--+--+|   ||   |DownV|  .  |       |  .  |DownV|   ||   |+--+--+|
 |   |   |   |+---+-----+  |  |       |  |  +-----+---+|   |   |   |
 +---|---+   +----|--------|--+       +--|--------|----+   +---|---+
     |            |        |             |        |            |
     +------------+        +---  ...  ---+        +------------+