Slide the alphabet along by a certain number of letters, e.g. 1 letter:
Plain text: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Code: B C D E F G H I J K L M N O P Q R S T U V W X Y Z A
SCOUT = TDPVU
NFFU NF JO UIF QBSL CZ NPPOMJHIU
Then attach the two wheels together using a split pin so that you can rotate them independently.
Now if you want to solve a cryptograph where the alphabet
slides along by 3 places, just rotate the wheel so that A
is opposite the C, and then you can read the code letters
off the wheel.
The Cryptograph Wheel below was published in 1869. It is slightly more complicated than ours, because the letters are in a random order.