Folder structure:
/
/src/
/src/PCL/
/src/PCL/Test/
/src/PCL/Test/MyClass.php
/src/index.php
--------------------------------------------------------------
index.php
<?php
use PCL\Test;

$test = new MyClass();
?>

MyClass.php
<?php
namespace PCL\Test;
class MyClass
{
	public function __construct()
	{
		print 'Welcome to MyClass!';
	}
}

?>