I guess you'll either love or hate this mind reading trick that you can perform with your Android device. Some of the comments about this app state that it's lame, and stupid and they figured it out right away. Really? Really!!???
If they figured it out right away, I believe it's because they recalled the paper method where the next box of numbers you chose depended on whether the previous one contained your selected number or not. Properly presented, the Android version is much smoother and more natural...and subsequently more amazing.
As with so many other magical effects, it's all in the presentation.