<? $bool = true; echo (int)$bool; ?>
<? $x = "100"; $x++; // $x is now 101 ?>
<? $moo = "xxx"; $a = "moo"; $$a = "boo"; echo "variable \$a is '$a' and \$moo is '$moo'.<br>"; // will output: variable $a is 'moo' and $moo is 'boo'; ?>