PHP Move up echo to fill up empty space

PHP Move up echo to fill up empty space

How should i do to populate array results into a box. And it should
continue to move up to fill the empty space with subsequent search if
earlier search resulted in null. And if earlier search is not empty, the
subsequent search will be populated in its own position accordingly.
Box
Result 1 // Search on $Arr1 for 'X'
Result 2 // Search on $Arr2 for 'X'. Move up if Result 1 is empty
Result 3 // Search on $Arr3 for 'X'. Move up if Result 1 or 2 is empty
I tried the following code, but it either doesnt move up to fill the empty
space if earlier search was empty nor can it fill up accordingly if more
than one result is not empty.
<?php
if (($pos1 = array_search('X', $Arr1, true)) !=== null){
echo $pos1; ?><br />
<?
} else {
if (($pos2 = array_search('X', $Arr2, true)) !=== null){
echo $pos2; ?><br />
<?
} else {
if (($pos3 = array_search('X', $Arr3, true)) !=== null){
echo $pos3; ?>
}
?>