•••••••••••••••••••••••••••••
  •·······················•  
   •·····················•   
     •·················•     
      •···············•      
        •···········•        
         •·········•         
           •·····•           
            •···•            
              •              
            •···•            
           •·····•           
         •·········•         
        •···········•        
      •···············•      
     •·················•     
   •·····················•   
  •·······················•  
•••••••••••••••••••••••••••••