consists of a square grid. The goal is to fill in each cell with numbers from 1 to N, where N is the size of the puzzle's side. No number may appear twice in any row or column. The numbers along the edge of the puzzle indicate the number of buildings which you would see from that direction if there was a series of skyscrapers with heights equal the entries in that row or column. The puzzle book contain: - 200 Puzzles - Handy 6 x 9 inch Book Layout - 2 Puzzles per Page - Ideal for both Beginners and Experts In the book you will find a description and examples of solutions for all puzzles. The book is for those who like logic and math problems. Decide, developing and improving.