// reference: https://www.php.net/manual/en/language.references.php
//
// by establishing a unused reference to an established array cell
// it allows it to be open to any modification.
//

<?php
    print("[-] Before unused reference\n");
    $array1 = array(1 => 1); // baseline array
    print_r($array1);

    $x =& $array1[1]; // configure unused reference

    print("[-] Using \$array2 to change value\n");
    $array2 = $array1;
    $array2[1]=2;
    print_r($array1);

    print("[-] Using \$array3 to change value\n");
    $array3 = $array1;
    $array3[1]=3;
    print_r($array1);
?>

/*
[-] Before unused reference
Array
(
    [1] => 1
)
[-] Using $array2 to change value
Array
(
    [1] => 2
)
[-] Using $array3 to change value
Array
(
    [1] => 3
)
*/