jquery ajax ส่งค่า Array 2d อย่างไร ครับ สามารถทำได้หรือไม่

<script>
$(document).ready(function(){
	var items = [[1,2],[3,4],[5,6]];
	$.ajax({
		url:"get.php",
		type:"POST",
		data:{'data[]':items},
		success:function(rs){
			alert(rs);
		}
	});
});
</script>

<?
$data = $_POST['data'];
print_r($data);
?>

<script>
var data = 	{
		               'room_id':ar_room_id,
			       'adult':ar_adult	
			}


$.ajax({
		url: "data.php",
		type: "post",
		cash: "false",
		data: {
				data : data
                          },
                success: function(in){
                         console.log(in)
                }
</script>

<?php
print_r($_POST);
?>