Activity Book for Adults: 500 Extreme Puzzles & 12 Puzzle Types (Sudoku, Fillomino, Battleships, Calcudoku, Binoxxo, Slitherlink, Sudoku X, Masyu, Jigsaw Sudoku, Minesweeper, Suguru, and Numbrix)
Sudoku X, Jigsaw Sudoku, Battleships, Calcudoku / Mathdoku
- Difficulty
- Extreme
- Puzzle count
- 500 puzzles