     ** **************     
     **   ...  **
     ****************
                            /   (   )
                                ..
                            .
                               ..
                               .
  1 )       (  DATA )   
              (  Census )   
                   
           
      -           -   -    
 2 )  ....             
       ...           ..
 3 )                  
                   
           ..      -      -
       
          ...    
                                     