请问二维数组矩阵算法

$ary = array(
	'a'=>array('a1','a2'),
	'b'=>array('b1','b2'),
	'c'=>array('c1','c2'),
);

echo '';
foreach($ary['a'] as $aV){
	foreach($ary['b'] as $bV){
		foreach($ary['c'] as $cV){
			echo "";
		}
	}
}
echo '
$aV
$bV
$cV
';

$ary = array(
    'a'=>array('a1','a2'),
    'b'=>array('b1','b2'),
    'c'=>array('c1','c2'),
);

echo "\n";
echo "\n";
foreach($ary['a'] as $m) {
  foreach($ary['b'] as $n) {
    foreach($ary['c'] as $v) {
      echo "\n";
    }
  }
}
echo "
a
b
c
$m
$n
$v
";