Key square

Imagine you are playing a game of hide and seek with your friends. You know they are hiding somewhere in your backyard, but you don't know where. Your friend tells you that they have left a special sheet of paper with clues that will help you find your friends. This special sheet of paper is called a key square.

The key square has a bunch of little boxes, like a checkerboard. Inside each box there is a letter or a number. These letters and numbers tell you where your friends are hiding. You just need to know how to read the key square to find them.

To read the key square, you have to match up the letters or numbers in the top row and the left column. Imagine you are looking for the letter "D" in the key square. You would look for the column with the letter "D" at the top, and then look for the row with the letter "D" on the left. The box where they meet is where you will find the letter "D" in the key square.

The key square can help you find things in a secret code or cipher, which is like a secret language. It's like a map that shows you where to find the letters or numbers you are looking for. With the key square, you can crack the code and read the secret message.