Turf is a logic puzzle invented by John Bulten (USA). A rectangular or square grid contains numbers in some cells. The goal is to shade some cells so that the grid will be divided into gray and white regions. Each region must contain at least one number. This number indicates the size of a region. If a region contains any other cell with a number, it represents how many surrounding cells are white, including itself and diagonal ones.
Cross+A can solve puzzles from