Night Duty is a timekiller-puzzle game. We came up with this game at work during the night shift. 3 x 5 = 6, because 1 and 5 digits are together 6. For example, if you see at the top of screen 9 you have to press 6 and 6(6 x 6 = 9(3+6), and then you get the next digit, the game will always go fast. Play it if you have nothing to do, so you can keep your brain active!