PHP嵌套foreach

我以为我理解PHP数组,但似乎我没有:(
这是我的代码：

<?PHP

// Create a magazines array
$magazines = array();

// Put 5 magazines on it
for($x=0;$x<5;$x++)
    $magazines[] = "Magazine " . $x ;


// Associate articles array to each magazine
foreach($magazines as $magazine){
    $articles[$magazine] = array();
    for($x=0;$x<3;$x++)
        $articles[$magazine] = $magazine . " - Article " . $x ;
}

// List them all
foreach($magazines as $magazine){
    echo $magazine . " has these articles: <br>";
    foreach($articles[$magazine] as $article)
        echo $article . "</br>";
}

?>

它只打印杂志,而不是每个杂志内的文章.很明显,我对嵌套的foreach循环有一些看法.请你帮助我好吗？我究竟做错了什么？提前致谢！