As a Christmas present, my kids bought me The Complete Sherlock Holmes, Volume I and Volume II. Inspired by the stories, I created some cryptograms for my kids to play with over the weekend.
The first cryptogram was a book cipher, which was clearly a hit!
To decode a book cipher, you first have to know what book to use. So I included a cartoon showing two of our bookshelves, along with enough information to identify the book to be used for decoding (it was The Wind in the Willows). Now, with the right book in hand, turn to each indicated page number and write down the word that is reached by counting the indicated number of words from the top of the page.
The second cryptogram was based on hidden words. To set the stage for the game, I hid a toy monster somewhere in the house, along with two quarters. Then I created an encrypted message; when decoded, the message reads as if the monster were asking for help. To allow for two players, I divided the cryptogram into two parts, one consisting of the odd-numbered words and the other consisting of the even-numbered words. It looked like this:
To decode the message, replace each word with a word that hides inside it. (For example, replace the word STAVE with the word SAVE.) Then bring the two halves of the message together to reveal the monster's plea for help—and its location in the house.