Suguru Puzzle Books for Adults : Tectonics Japanese Math Logic Number Puzzle 500+ Puzzles Easy to Hard
Easy Logic Puzzles & Brain Games for Adults : 500 Puzzles & 12 Puzzle Types (Sudoku, Fillomino, Battleships, Calcudoku, Binary Puzzle, Slitherlink, Sudoku X, Masyu, Jigsaw Sudoku, Minesweeper, Suguru,