$qwe='knot';
function(){
  echo $qwe;
}

define('q',new ArrayObject($_POST));
function(){
  echo q->qwe;
}

function test(){
    echo $GLOBALS['qwe'];
}

$GLOBALS['qwe'] = 'knot';
test();

class GlobalClass
{
    static $_stack = array();
    static function get($key) {
        return (isset(self::$_stack[$key])) ? self::$_stack[$key] : NULL;
    }

    static function add($key, $value = NULL) {
        self::$_stack[$key] = $value;
    }
}

function test(){
    echo GlobalClass::get('key1');
}
GlobalClass::add('key1', 'value1');
test();

class GlobalClass
{
    public $_stack = array();
    function get($key) {
        return (isset($this->_stack[$key])) ? $this->_stack[$key] : NULL;
    }

    function add($key, $value = NULL) {
        $this->_stack[$key] = $value;
    }
}

class NowClass extends GlobalClass {
    function __construct() {
        $this->add('key1', 'value1');
    }
    function test() {
        echo $this->get('key1');
    }
}

$class = new NowClass;
$class->test();

$global_stack = array();
function global_get($key)
{
    global $global_stack;
    return (isset($global_stack[$key])) ? $global_stack[$key] : NULL;
}
function global_add($key, $value = NULL)
{
    global $global_stack;
    $global_stack[$key] = $value;
}

class NowClass {
    function __construct() {
        global_add('key1', 'value1');
    }
    function test() {
        echo global_get('key1');
    }
}

$class = new NowClass;
$class->test();

$asd='what about this?';
class q{
    public function __get($qwe){
        return $GLOBALS[$qwe];
    }
    public function __set($qwe,$val){
        $GLOBALS[$qwe]=$val;
    }
}
$q=new q;
echo $q->asd;
$q->asd=' or even this?!';
echo $q->asd;