Imagine a grid of letters arranged in rows and columns.
At first glance the letters in the array may appear completely random.
However, if you look a bit more closely, you may perhaps spot a word running horizontally or vertically within the grid.
If you look even more closely you may then spot another word, with a completely different starting point and most likely in an entirely different orientation.
This is what is known as a "mystery word puzzle", or sometimes "word search puzzle" or "word find puzzle".
The goal being, to find all the words (there can be quite a number) hidden within the letter grid.
Mystery word puzzles are very popular in newspapers and magazines, and are suitable not only for adults, but even relatively young children.
The task in solving puzzles is easy to explain, but accomplishing it can be quite a challenge, especially if you are only given a rough idea (perhaps a topic or theme, and the total number of words) of what you are supposed to be looking for.
In the case of children, these types of puzzles can be used to help them pay attention to the exact spelling of words, and also perhaps introduce them to new words.
Of course, children can get frustrated if the puzzle is too difficult, so they are generally given a list of the exact words to look for, the grid is kept relatively small, and particularly in the case of younger kids, hard-to-spot word orientations such as right-to-left are used less frequently, or even avoided entirely.
While solving mystery word puzzles is one thing, creating them is another.
You might want to do this if you publish a newsletter or magazine, or if you're a teacher using word searches as a classroom or school activity, perhaps to teach spelling.
I am sure in the olden days, these puzzles were once created entirely with pen, paper and brain power - but if you try this yourself, you will soon see just how difficult this is.
Today of course there is an easier way: with the help of a computer and some mystery word puzzle maker software you can create puzzles very quickly and easily.