------------------------- 
   /                        /| 
  /            A           / / 
 /                        /A/| 
 ------------------------- / | 
 |           A           |/  | 
 -------------------------   | 
 |   |               |   | B | 
 |   |               |   |   / 
 | B |       C       | B |  /| 
 |   |               |   | / / 
 |   |               |   |/A/  
 ------------------------- /   
 |           A           |/    
 -------------------------
- ODER -
---