400 NUMBRICKS puzzles 9 x 9 HARD + BONUS 250 LABYRINTH 25 x 25: Sudoku with HARD levels puzzles and a Labyrinth very hard levels

400 amusing Numbricks classic puzzles + bonus in 250 Labyrinth 25 x 25 very difficult levels (bonus puzzles need to be downloaded and printed). The way to mastery of Sudoku! 400 unique Sudoku puzzles. Fitness for your brain. Original Sudoku for the power of your brain. Just tested puzzles. Answers at the end of the book. All riddles have only one proven solution. Good mind support in the excellent form. Develops memory, logical thinking, helps to focus. Creative possibilities expand. Ideal ...