It’s a little thing, but the instructions for the “Rotational Cipher” exercise say, “The Caesar cipher … relies on transposing all the letters in the alphabet using an integer key between `0`

and `26`

,” but since there are 26 letters in the English alphabet, the index must be between 0 and *25*, right?

Not exactly. `ROT26`

will return the value as `ROT0`

because you are working Modular arithmetic on this exercise as stated in the instructions. This implies that `ROT27`

and `ROT1`

will also produce identical outcomes, and the pattern continues similarly.

Got it. I was thinking of an array index.