X                  X
X    D        D    X
X   DD        DD   X 
X  DDD        DDD  X
X DDDD        DDDD X
X   DD        DD   X
X     DDD  DDD     X
X   DDDDD  DDDDD   X
X DDDDDDD  DDDDDDD X
XDDDDDDDD  DDDDDDDDX
XDDDDDDDD  DDDDDDDDX
X DDDDDDD  DDDDDDD X
X   DDDDD  DDDDD   X
X     DDD  DDD     X
X   DD        DD   X
X DDDD        DDDD X 
X  DDD        DDD  X
X   DD        DD   X
X    D        D    X
X                  X
     