If you think you can solve all our puzzles, You are a genius Our "Escape puzzles" book is made exclusively for people who want to raise their brain competencies and strengthen their mathematical mindset.You can use a timer and set a limited time during the process of solving the puzzle and reach the end-door of it. We recommend you to decrease the timing each time you reach another level difficulty and make it tougher.Our book is large printed easy-to-use.If you like our work, please let us know with your reviewMade with LOVE