No Four in a Row puzzle book for Adults

The book contains 200 excellent No Four in a Row puzzles at the level Hard.
50 puzzles 7x7 75 puzzles 9x975 puzzles 11x11 All riddles have only 1 solution. 2 puzzles per page. The font size is correct you will not have to strain your eyes when solving puzzles.High quality paper and print (all puzzles read well, easy to write with pen and pencil without worry of bleed-through).
No Four in a Row is played on a rectangular or square grid. Some cells of the grid contain 'X' and 'O'.The task is to fill in the grid so that four consecutive identical symbols never appear in any row, column or diagonal.