<?php

	class X {}

	$x = new X;
	$x->f = 6;
	$y = &$x->f;
	$z = &$y;

	// unset remove $y from the COW set, but it doesnt affect the value of $x or $z	
	var_dump ($y);
	unset ($y);
	var_dump ($y);

	var_dump ($z);
	$z = 5;
	var_dump ($x);

	unset ($z);
	var_dump ($x);
?>