Hard Logic Puzzles & Brain Games for Adults: 500 Puzzles & 12 Puzzle Types (Sudoku, Fillomino, Battleships, Calcudoku, Binary Puzzle, Slitherlink, ... (Challenging Fun Brain Teasers Series)
Hard Logic Puzzles & Brain Games for Adults: 500 Puzzles & 12 Puzzle Types (Sudoku, Fillomino, Battleships, Calcudoku, Binary Puzzle, Slitherlink, ... (Challenging Fun Brain Teasers Series)