Direct communication between cell phones using flashlight and camera

Aside from Wi-Fi and Bluetooth near field communication (NFC) cell phones can communicate (theoretically) by sending signals with a camera flashlight and receiving them with a camera. As alternative, the phone's screen can be used as a transmitter.


Here is document (a copy) and video describing similar communication method.

Also there are mysterious Morse Code apps I have to explore: http://www.androidzoom.com/android_applications/morse+code+communication