Hard, Harder and Hardest Puzzles: Sudoku Hard To Extreme Edition - Paperback

by Puzzle Pulse (Author)

The puzzles in this book will only get more challenging the longer you play. A progressive game will push you outside of your comfort zone. You grow better when you're tested, and that means mental development. You will notice that your logical thinking and creativity will improve, as manifested by the speed of solving. Get a copy today!