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Monday, October 17, 2011

Secret Decoder Wheel

The cryptograms discussed last week are a kind of substitution code, in which one letter is replaced by another. Some of the other codes listed a few days ago (such as Morse code and semaphore) are also based on substitutions, but with special symbols replacing the letters. You can make your own special code by creating your own symbols - a personal alphabet! If you tell your friends what the symbols mean, you can send secret messages back and forth.

You can even make a secret decoder wheel using this pattern.

What You'll Need:
Secret decoder wheel pattern

Cut out the two wheels. Write a 36-symbol secret alphabet in the spaces of the inner (smaller) wheel. There's room for the letters A - Z and the numbers 0 - 9. Line up the two wheels so that the black dots are on top of each other. Push a thumbtack through the black dots and stick the point into an eraser so that you don't hurt yourself. Turn the inner wheel to line up one of your symbols with the letter "A"; this is called the key. You can then read all the other letters directly. Don't forget to make another wheel for your friend who will receive your messages, and to give him or her the key!

If you later want to create another code, you can simply line up another symbol with "A", and tell your friend what the new key is! Happy coding!

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