*
*
  GGGGGGGGGGGGGGGGGGGGGGGGGG
  GGGGGGGGGGGGGGGGGGGGGGGGGG
            b               
*
GGGGGGGGGGGGGGGGGGGGGGGGGG  
GGGGGGGGGGGGGGGGGGGGGGGGGG  
*
     k           k          
*
BBBBBBBBBF   DBBBBBBBBBBBBBB
AAAAAAAAAE   CAAAAAAAAAAAAAA
AAFAAAAAAE   CAAAAAAAAAAAAAA
AAAAAAAAAE   CAAAAAAAAAAAAAA
 A                          
 A     b         q          
 A                          
 ABBBBBBBBBD  GGGGGGGGGGGG  
 AAAAAAAAAAC  GGAAGGGGGGGG  
 AAAAAAAAAAABBGGGGGGGGGGGG k
*
*
GGGGGGG  DBBBBBBBBBBBBBBBBBB
GGGGGGG  CAAAAAAAAAAAAAAAAAA
*
*
BBBBBBBBBBBBBBBB@@BBBBBBBBBB