Crossword puzzles began to gain popularity in the 1920's following the publication of Simon & Schuster's first book of puzzles. Today, Simon & Schuster's rules regarding American crosswords are taken as the standard for puzzle design:
- The height and length of a puzzle must be the same, and must be an odd number of squares. The standard size is 15 by 15 squares, though larger sizes are quite common
- The smallest allowable word size is three letters, and the diagram must have the same layout when turned upside-down.
- The number of black squares must be confined to less than one-sixth of the grid.
- Each white square must be part of an across answer and a down answer.
Many puzzles have "themes", in which the longer answers have a shared trait. Because of this, these particular answers usually have very carefully-worded clues that could not be deciphered without many of the answer's blanks already having been filled in. A puzzle by Pancho Harrison which appeared in the May 2009 issue of GAMES Magazine, contained theme answers of "AREWETHEREYETI", "THEFAIRSIDE", "BORNTORUIN", "ANTIFARMS", and "SALIVATIONARMY". You can see that the common thread running through these answers is that they are more commonly recognized phrases and titles, each with the addition of a strategically-placed "I". The title of this puzzle was "Assert Yourself" (get it?).
Puzzles are generally constructed from theme answers first, then creating a layout for the grid to accommodate these answers. After this, the grid is then filled out and clues are written.
