asco-o:         SO                    
                 |                    
                 |                    
              +--+     +  AO          
              |        |  |           
              |        |  |           
              +   AS---+--+           
              |        |              
              |        |              
              +    0   +--A           
              |    |   |              
              |    |   |              
              +----A---+              
     AA       |    |   |  O    CA     
     |        |    |   |  |     |     
  +--+--+--+--+----+---+--+--+--+--+  
           |  |    |   |     |     |  
           |  |    |   CO   CO     SO 
        A  S  C O--+-O                
        +       |  |   O  OO C        
        |       |  |   |  |  |        
 -+--+--+--+----+--AS--+--+--+--+--+- 
     |  |       |  |   |     |  |  |  
     A  AS      O  |   S     CO OA CC 
                   +                  
            AO     |   OO S           
             |     |   |  |           
            -+--+--+---+--+-          
                   |