Crossword grids such as those appearing in most North American newspapers and magazines feature solid areas of white squares. Every letter is checked (i.e. is part of both an "across" word and a "down" word) and usually each answer must contain at least three letters. In such puzzles shaded squares are typically limited to about one-sixth of the total. Crossword grids elsewhere, such as in Britain, South Africa, India and Australia, have a lattice-like structure, with a higher percentage of shaded squares (around 25%), leaving about half the letters in an answer unchecked. For example, if the top row has an answer running all the way across, there will often be no across answers in the second row.