¡Desbloquea tu teléfono con la retina de tu ojo! (broma)
Lockscreen using retina - use your eye to unlock your mobile phone! This app pretends to detect your eye and uses it to unlock the mobile phone screen. It's a customizable lockscreen which pretends to detect your eyes to unlock. Of course it's only a prank. Just set backup password and use it everyday. Your phone will be safe now!
Tell your friend that it detects your eye and then unlocks phone. Give him the phone and see how he is trying to unlock the screen. Then click on green dot in hiding, so that your friend will not see this. Phone will unlock!