[ _ 3 _ _ 1 _ _ _ _ ]
[ 4 _ _ _ _ _ 2 _ _ ]
[ _ _ _ _ _ _ _ _ _ ]
[ _ 7 _ _ _ _ _ _ 6 ]
[ _ 1 _ 3 _ _ _ _ _ ]
[ _ _ _ 2 _ _ 5 _ _ ]
[ 2 _ _ 5 _ 8 _ _ _ ]
[ 6 _ _ _ _ _ _ 1 _ ]
[ 5 _ _ _ _ _ _ 7 _ ]