^                        t                                                    
  |                     t  t                                                    
  |         t           t  t     t                                              
  |   t  t  t  t  t  t  t  t  t  t  t  t                                        
  |   t  t  t  t  t  t  t  t  t  t  t  t                                        
  |   t  t  t  t  t  t  t  t  t  t  t  t     t                          t       
  |   t  t  t  t  t  t  t  t  t  t  t  t  t  t  t  t          r      t  t       
  |   t  t  t  t  t  t  t  t  t  t  t rt  t  t  t  t          r  r   t  t  t    
  |   t  t  t  t  t  t  t  t rt rt rt rt  t  t  t  t          r  r   t  t  t    
  |   t  t rt  t  t  t  t  t rt rt rt rt  t  t rt  t  t  t  t rt rt  t  t  t    
 -+---------------------------------------------------------------------------> 
  |  10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09