Mind Reader Book

For centuries, many people tried to find this ancient object, and now its on your own hands: the Mind Reader Book! You think of a number, and it tells you what you thought!
Much more than magic, its plain math beauty. Pick mentally a number and, through the books pages, youll mark the ones in which your number appears. By simply doing these marks (on the pages, not on the numbers), the book can completely read your mind and tell which number you just thought. Doubt it? So give it a try, and enjoy it with your friends!