cities

                             ^
                _______     ^^^
               |xxxxxxx|  _^^^^^_
               |xxxxxxx| | [][]  |
            ______xxxxx| |[][][] |
           |++++++|xxxx| | [][][]|      METROPOLIS
           |++++++|xxxx| |[][][] |
           |++++++|_________ [][]|
           |++++++|=|=|=|=|=| [] |
           |++++++|=|=|=|=|=|[][]|
___________|++HH++|  _HHHH__|   _________   _________  _________
         _______________   ______________      ______________
__________________  ___________    __________________    ____________