O                
         H_/_|_\_H            
         H |   | H            
                              
                              
                              
                              
                              
                              
                              
                              
                              
                              
                              

                              
                              
                              
                              
                              
                              
         H___O___H            
         H  |||  H            
           |   |              
                              
                              
                              
                              
                              
                              
                              
                              
                              
                              
                              

                              
                              
                              
                              
                              
         H_______H            
         H  \O/  H            
            _|_               
           |   |              
                              
                              
                              
                              
                              
                              
                              
                              
                              
                              
                              

                              
                              
                              
                              
         H_______H            
         H  \O/  H            
             |                
            / \               
           |   |