As programmers, we regularly work with text encodings. But there’s another sort of encoding at work here, one we process so often and so rapidly that it’s invisible to us, and we forget about it. I’m talking about visual encoding — translating the visual glyphs of the alphabet you’re reading right now. The alphabet is no different than any other optical machine readable input, except the machines are us.

But how efficient is the alphabet at encoding information on a page? Consider some of the alternatives — different visual representations of data you could print on a page, or display on a monitor:

5081 punch card
up to 80 alphanumeric characters

Maxicode
up to 93 alphanumeric characters