The audience is now divided into two groups: the techno-Muggles are staring at the comic, wondering WTF it’s supposed to mean. The rest of us are laughing hysterically, perhaps literally ROFL*, at the thought of counting sheep using signed integers. Who but Randall Munroe would have thought of a cartoon gag about twos’ complement math?
This is a great example of why XKCD is so cool. Only once in a great while will a comic come along that truly Gets It and shows us another aspect of Truth. Calvin and Hobbes, Non Sequitur, and The Far Side come to mind. This is great stuff. But don’t just take my word for it — take a look at some for yourself!
* Note to self: Don’t read XKCD at work anymore, even on break. The Muggles will hear you laughing for sure!