<?php
    class Construction {
        var $area;
        function __construct($area) {
            $this->$area = $area;
        }
        function __destruct() {
            echo "Leaving {$this->area}\n";
        }
    }
    
    $c = new Construction('London');
    $vegas = $c;
    $vegas->area = "Las Vegas";

    echo "\$c = NULL\n";
    $c = NULL;
    echo "\$vegas = NULL\n";
    $vegas = NULL;
? >

$c = NULL
$vegas = NULL
Leaving Las Vegas
EOS