#polyalphabetic cipher

The gist for how it works to encode is that you alternate which of the wheels you use for the input (so for the first letter, you’d encode by pointing a letter to the arrow on the first wheel, then you’d switch to the second, and so on).    

I couldn’t decide at first whether I wanted the wheels to be purple or teal, so I went with purple for the front and teal for the back. In hindsight, the teal probably captures the Barbie typewriter vibes better than the purple, but oh well.