Harris remembered an Air Force instructor who had shown him a secret code based on a five-by-five alphabet matrix. Each letter was communicated by tapping two numbers: the first designated the ...

Once you have your circles, you need to write the alphabet around the outside ... This will let you make secret number codes later. Put the small circle with the letters on it on top of the ...

The accepted story is that the first alphabet developed in the Sinai Peninsula around 1,900 B.C., an innovation on Egyptian hieroglyphics, but a discovery in a tomb in Syria challenges that narrative.