If you would like to download the app we created for this activity it is available on the Mobile Devices page for Android phones and tablets.
http://thebeacon.bhs.edu.hk/course/view.php?id=4325
Just tap the cloud to download it and then install the app using any file browser (ES Explorer, Root explorer, Astro, etc..)
The boxes we placed at each point are no longer at the park though.