All the sources codes "But why ?"page 46

<?php

Class Aire {

function Aire(){
        $this->_validation = new ValidationManager(
            new Aire,
            new Aire
            );
    }
}

?>

thread.start();
while (thread.isAlive())
{
	SystemClock.sleep(1);		    	
} 

<?
if(true){?>
<?=$var?><td><?
}
?>