The book contains 400 Snake puzzles 9x9Medium puzzles 200 Hard puzzles 200 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). Snake (also known as "Tunnel") is a kind of logic puzzles. It is played on a rectangular or square grid, where two cells are marked. The task is to draw a single line ("snake") between marked cells; this line never touches itself, not even diagonally. Numbers outside the grid show how many cells must be blackened in the corresponding row or column.