Creating Life As We Don’t Know It - Issue 6: Secret Codes
▻http://nautil.us/issue/6/secret-codes/creating-life-as-we-dont-know-it
Back in the 1970s, you might open up a box of cereal one morning and out would fall a cardboard disk. It was a code wheel, which allowed preteen cryptographers to ply their trade. The wheel had two disks of unequal size, joined at the center, so that you could turn each of them on the common axis. Letters ringed the outer wheel, and the inner wheel was marked with an arrow. If you lined the arrow up with a letter, a window in the inner wheel revealed a different letter. You could write out (...)