Mixed Puzzles Activity Book For Adults: 200 Medium To Very Hard Puzzles & 6 Puzzle Types (Jigsaw Sudoku, Battleships, Fillomino, Minesweeper, Futoshiki, Skyscrapers)
Hard To Extreme Jigsaw Sudoku - 100 Challenging Puzzles: Irregular Sudoku Puzzle Book For Adults - Extremely Difficult Sudoku Variant For Advanced Players
2021 Activity Book For Adults: 365 Hard Variety Puzzles For Every Day Of The Year : 12 Puzzle Types (Sudoku, Futoshiki, Battleships, Calcudoku, Binary Puzzle, Slitherlink, Killer Sudoku, Masyu, Jigsaw