Crossword Puzzle Grids

Before you do your next crossword puzzle take a moment to look at the grid. Crossword grids are neat to look at. The pattern of black and white squares makes a picture. But they aren't just random patterns. Constructors must follow a few rules when they design a puzzle grid.

Here are a few of the rules.
1. Grids must have rotational symmetry. That means if you turn the puzzle upside down the pattern of black and white squares should look the same as it did right side up. Try it and see.

2. Don't use too many black squares. Fewer black squares means more words and longer words.

3. No unchecked words. That means every square should have a letter from an across answer AND a down answer.

Of course, sometimes the rules are broken to make interesting Grid Art. Check out this link to see some examples.