ShamShuffle
Please press more than 0.2 seconds the START button!!
What should you be when you decide things?
Coin toss? Dice roll? No, you should use ShamShuffle.
You will surely win if you use this app.
If you press more than 0.2 seconds the START button, you can choose the cup the ball comes without fail.
You can not when you press the START button normally, to select the cup the ball comes.
The Try that once by all means.