gistfile1.php

<?php 
        $global = array();

        $reference = &$global;
        $copy = $global;
        
        $global[] = "global";
        $reference[] = "reference";
        $copy[] = "copy";

        print_r($global);                       
        print_r($reference);
        print_r($copy);

        print $global === $reference;   
        print $global === $copy;
        print $reference === $copy;