class output{
	public $data=array();
	function __construct__(){
	}
	function setSomething(){
		$this->data[] = 'frog';
	}
}

class template{
	function __construct__(&$output){
		$this->output = $output;
	}
	function myFunction(){
		print_r($this->output->data;)
	}
}

$output = new output();

$template = new template($output);

// What I had added: $template->output = $output;   <=== STUPID

$output->setSomething();

$template->myFunction();