Any arrangement of intersecting words with a set of accompanying clues can be considered a crossword puzzle. However, there are a few rules of thumb that good crosswords typically follow, which make them more satisfying to solve.
Start by building a grid of connected words. The more intersections the better, as this helps puzzle solvers figure out more difficult clues once they've answered a few easier ones.
Consider this example of a poorly constructed puzzle:
Even when you know most of the answers, there isn't enough interconnectivity between words to help you solve the last one.
The addition of one more word and intersection pair helps the puzzle solver, as shown here:
The addition of an easy connecting word with two intersections helps the puzzle solver get a foothold and narrow in on the answer "FLORID".
As you can imagine, the more connections you make, the more each word can help the solver with the others.
Start with a moderate size grid which will allow you to use enough words to give the player a chance! A 15 x 15 grid is fairly standard, and is used for the daily New York Times puzzle (the Sunday puzzle is 21 x 21).
Professional crossword constructors will make their grids with very few black squares (roughly 15% black), comprised of around 70-80 words, and with a rotationallly symmetrical mirror pattern, as shown here.
This is a great goal, but very difficult to create, so we'll loosen up the rules a bit when we're first starting!
While there's nothing better than an expertly crafted word grid, we'll use technology to assist our efforts. There are many software crossword generators available as apps or in-browser that can take a list of words as an input, and then create an interlocking grid of those words within a set of specified constraints.
A great way to increase the odds of making a high quality grid is to begin with a very long list of words and then allow the software to generate the grid. Remove any words that have a hard time fitting or get stranded off to the sides on their own islands.
Here are some miniature grid examples, using the online generator Armored Penguin Crossword maker.
This grid was made with an 8x8 grid and a very small word list. It wasn't able to make a successful puzzle, so we'll try again with a larger grid and longer word list.
Here, we've increased the number of words in the list, and the grid has improved somewhat. There are a lot of black squares and the grid is larger, but at least there are no islands.
We can look at this grid and see some potential problem words. What happens if we change "puppy" to "puppies"? swapping the 'Y' for an 'IES' may make it easier to connect words.
You can see that the grid has expanded again (to an awkward 14x15), but the density seems a bit better. This iterative process of adding to and changing your word list and then allowing the software to try new grid solutions can take some time, but lead to pretty good results.
At some point, you may decide to abdicate some control over you word list to the software. You can use your word list as the foundation, and then allow the software to pick words from a dictionary that can help it fit an optimal grid.
Unfortunately, most online puzzle constructors don't offer dictionary grid fills, but there are some excellent downloadable options for all platforms. Additionally, dedicated crossword creation software offers options to manually design the grid, and fill in grid letters individually for total control.
Crossfire is very popular on mac os, and Crossword Compiler is a great choice on Windows. Both of those are $50 for a license, and offer a huge array of options. They are often used by professional crossword constructors.
If you're on an iPhone or iPad, check out the excellent, and free Crossword Maker for Cruciverbalists (CMFC).
Here's an example of the previous puzzle moved into CMFC.
Note how it already has done a nicer job of solving the grid in an 8x8 square with no islands.
Next, we'll start to manually add words to improve the grid. The software will even make suggestions of words from its dictionary as you start to type.
Now that we have a word grid we like, we get to start writing clues! This is where you can really get creative and tune the difficulty level of the puzzle.
For example, look at the word 'ATL'. You could make it very easy:
19. "Airport code for Atlanta"
19. "Braves on MLB scoreboard"
Or fairly hard:
19. "Hub for 777 in GA"
Here's our finished puzzle with the clues added.
And, here's the blank version, ready for solving.
Finally, here's a special Adafruit themed crossword for you to print out and try.
Here's the solution sheet if you want to check your answers later!
Next, we'll look at making word search puzzles.