Say I have a bunch of words that I want to make a word-search out of. What are some strategies for making a challenging but doable word-search puzzle where these are the words to be found?
I'm planning to post an answer myself with some ideas I've come up with. But I've never actually made a word-search puzzle and haven't solved many either, so I'd be grateful for input from those who have. Let's get a nice long list of techniques!
Some more points
Choose an easy-to-the-eye font and letter-spacing. The overall "look" is very important!
Consider crossings, i.e. have some letter be part of more than one word
Ensure that the number of "needed" letters and the number "filler" letters are in a "good" proportion. This may depend on you intention though. There are word-searches where all letters are part of some word, and ones with a lot of empty space. If the second category, don't have too many fillers.
Keep an eye on overall statistic. Each language has a certain distribution of 'likely letters' - your fillers should represent this as well.
You can make things interesting, by having the overall shape of the puzzle something else than a rectangle, or by having the 'fillers' end up in useful pattern etc.
Give the word-search some common "topic", don't choose arbitrary words.
You could also consider going with a differently aligned grid if you want to be original (like a diamond shape or an octogon) - you can also like in the example below complicate things by putting multiple letters as one:
Some ideas I came up with:
Consider the orientation (leftwards, rightwards, upwards, downwards, all 4 kinds of diagonally) of words to be found. Include at least a few words in each of these directions. Rightwards and downwards are the easiest to find, diagonally (other than southeastwards) the hardest - take account of this when deciding how difficult you want the puzzle to be.
Consider what 'fillers' (letters in between the words to be found) to put in. Use too many X's and Q's and the puzzle will be too easy; you should use a similar distribution of letters to the distribution in the words to be found.
To increase the difficulty, use red-herring words. If one of the words to be found is STACK, then throw in a STALK and a SACK somewhere and sprinkle loads of S's, T's, A's, C's, and K's around where STACK actually is to make it hard to find the right word.
For the "filter" letters, I would not consider using the same distribution, but equalize its distribution. For instance, if you have only one 'Z' in the words to search for, keeping the same distribution for filters would mean approximately 'add another Z in the filters'. So searching this word would be easy.
Whereas equalizing the distribution would mean words a bit more difficult to find. For instance, if you have 5 'E', 3 'M' and 1 'Z', try to insert 1 'E', 3 'M' and 5 'Z' as filters, so that all letters have 6 occurrences in your grid. Doing so will require a bit more difficulty to find words with rare letters.
EDIT:
A simple algorithm to implement this would be:
If you want your puzzle to be really hard here are some things to try:
Avoid words that read left to right (for languages naturally read in that direction), top to bottom (in all languages I think), and horizontally or vertically when at the edges of the grid. These are all easy to spot even if no clues are provided.
Giving a list of words to find makes things a bit too easy. A hint at some connection or theme if the words are really obscure might be okay. Of course if you want your puzzle to be really hard just use the most obscure words you can think of and only provide the number of words to be found (if you do this you will need to check thoroughly that no extra words have crept in.)
If you feel the need to provide a list of words use fragments of those words to fill in blank spaces. Placing the start fragment of a word near the beginning or end of a complete word is great way to create a wild goose chase. Fill the remaining single spaces with the least common letters from your clues, you want to make sure that if a letter only appears once or twice in all your you use it at least three or four times to fill in blank spaces. Any strings of letters that appear repeated across many of your clues will be any easy target to search for so make sure you use those to fill spaces. The more red herrings the better.
To make a puzzle really time consuming make it really large. Spotting a word and finding another that begins or ends nearby, or crosses it, makes things too easy. Having a grid large enough to space your words out nicely can completely eliminate this.
If capitalization is not important to any of the words, randomising between upper and lower case can make a word search fiendishly difficult to read. if you want a puzzle that is really difficult just to read, try a textured background and patterned letters. I'm thinking of camouflage schemes for the letters and background to are so similar you can hardly see the letters.
To be really unfair why not swap some letters for numbers or symbols, 0 for o, ( for c, that sort of thing.
A most wicked twist is to allow words to wrap around the edges of the grid. This is particularly unfair if there is no reason to expect you would do this. So to be really cruel make sure you give no hints this is what you are up to.
Of course if you are not a complete sadist then ignore this advice. If you want to make a nice easy puzzle do the opposite. A good word search will have just the right amount of cruel and kind elements. The right balance depends on your target audience.
