the game in the U.S.

The 1930s and 1940s marked a period of conscious experimentation and innovation in which constructors deliberately designed different kinds of puzzles to see their effects on solvers. Naturally, some designs were more popular than others. Constructors took a "survival of the fittest" approach which led to the demise of some designs and the success of others. Solvers and constructors took sides; some new designs engendered controversy among opposing factions. Individual constructors, editors, and publishers developed styles which in turn developed followings.

During the 1930s and 1940s in the United States this developmental process propelled the puzzle into a serious adult pastime and popular crossword designs gradually began to emerge as standbys. Among these new ideas was the concept of the theme puzzle. A theme puzzle is a crossword in which some or all of the clues revolve around a single, unifying or dominant idea or motif. The mes can vary widely from one puzzle to another. A theme might be a particular work of art, the corpus an author, to a consistent way of constructing answers by combining two words into one.

Another important innovation in the U.S. involved the definition of a puzzle's structure. A puzzle's structure is the pattern or layout of the black and white squares that make up the puzzle's rows and columns. The black and white squares must be laid out inside a large square polygon with four equal sides; and the white squares must be interspersed by a suggested percentage of black squares. Furthermore, the pattern of black and white squares must be symmetrical within the large square polygon. Symmetry is achieved when the black and white squares are placed next to each other so that their pattern remains unchanged when the large square polygon is held up by any edge and rotated until it's upside down. After rotation, the pattern will be exactly the same as before!

This American crossword puzzle structure is not standard in the sense that it is regulated or that constructors are obliged to follow it; variations exist. However, its grid structure is traditional and it conforms to a de facto standard; puzzles designed like this are published most often in in America and most constructors voluntarily follow this design most of the time. theydo so because it is tried and true and because solvers find it agreeable. (More about grid patterns elsewhere in this feature.)

Margaret Farrar

The theme puzzle and the standard U.S. grid structure are the original contributions of Margaret Farrar, a seminal figure in the field of the crossword puzzle. During the 1930s and 40s she devised most of the defining characteristics of the U.S. crossword  puzzle.

Many U.S. crossword puzzle innovations and de facto standards originated with the tenure of Margaret Farrar as editor of the New York World and the New York Times crossword puzzle columns. Referred to by some as the First Lady of Crosswords, her occupancy of that illustrious chair was perhaps the most fruitful and salubrious in puzzle history. On her watch, many of the key characteristics of the modern American puzzle were devised and established as de facto standards.

• Explore Margaret Farrar's place in the history of the game and her contributions to crossword puzzles. See a description of the definitive characteristics of the U.S. crossword at the Muse's biography of Margaret Farrar: click here.
• Explore the grid structure of the American-style puzzle further at the Wikipedia web site page on Types of Grid. Compare grid-styles popular in Britain, Australia, Japan, and other countries: click here.