When you buy this book you get an electronic version (PDF file) of the interior of this book. Hidoku is a fun and addicting logic puzzle game. It is very similar to Numbricks. The goal of Hidoku is to fill in the missing numbers, in sequential order, going horizontally, vertically and diagonally. Unlike Numbricks, diagonal paths are allowed. This book is ideal for you if you already know how to solve Hidoku puzzles but you find our hard Hidoku puzzles too difficult. You will experience Hidoku 20x20, Hidoku 25x25 and Hidoku 30x30. You get the perfect mix of different sizes of Hidoku to keep you entertained for weeks. Once you pick up this book, you won't be able to put it back down. You have been warned! Only 1 Hidoku puzzle per page, with lots of white space for scribbling. Hidoku Mixed Grids - Medium is a collection of 156 puzzles: 42 medium Hidoku 20x20 puzzles 42 medium Hidoku 25x25 puzzles 42 medium Hidoku 30x30 puzzles 30 extra logic puzzles The goal of Hidoku is to fill the grid with consecutive numbers that connect horizontally, vertically, or diagonally. In every Hidoku puzzle, the smallest and the highest number are presented in the grid. I guarantee that every logic puzzle in this Hidoku puzzle book has been carefully checked to ensure that each puzzle has only 1 solution. None of the puzzles in this book will appear in any of the other PuzzleBooks.net books. Hidoku is also known as Number Snake.