$arr1 [0] [0] = 00
$arr1 [0] [1] = 01
$arr1 [1] [0] = 10
$arr1 [1] [1] = 11

$arr2 [0] [0] = 00
$arr2 [0] [1] = 01
$arr2 [1] [0] = 10
$arr2 [1] [1] = 11