CI Calendar with multiple events per day

Hi!

I have something like this:
http://iv.pl/images/35021795344086662308.png

Now, I need to display more than 1 event on the same day, how do this?

Controller:

PHP Code:

public function index() {

 $data = array(
 3  => 'Draft Robot Plans',
 7  => 'Delivery of Robot Parts',
 13 => 'Construction Finished',
 13 => 'Another note on the same day',
 26 => 'Kill All Humans!'
 );

 $vars['calendar'] = $this->calendar->generate('', '', $data);

 $this->load->view( 'WEB/Index', $vars );

 } 


View:
(in View I only display variable 'calendar')