$a:
A Object ( [x] => instance A [name] => )
$b:
A Object ( [x] => instance B [name] => Jsem klon / instance A )
$c:
A Object ( [x] => instance B [name] => Jsem klon / instance A )
unset($a):

$a:

$b:
A Object ( [x] => instance B [name] => Jsem klon / instance A )
$c:
A Object ( [x] => instance B [name] => Jsem klon / instance A )