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