 
         
     1d
                                            
                                        
                        
                        1d
                    
                     
     2d
                                            
                                        
                        
                        2d
                    
                     
     
     
     
     
     1d
                                            
                                        
                        
                        1d
                    
                     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
    