Allison Johnson, writing in The Verge:

… the original Apple II version [of the video game Karateka] included a delightful little easter egg from the early days of PC gaming — putting in the floppy disk upside down would boot up the game upside down.

According to [Karateka’s creator Jordan] Mechner, the game’s developers hoped that a few people would discover it by accident, and think their game was defective. “When that person called tech support, that tech support rep would once in a blue moon have the sublime joy of saying, ‘Well sir, you put the disk in upside-down,’” Mechner was quoted as saying in a recent profile, “and that person would think for the rest of their life that’s how software works.”

It may seem disingenuous to suggest users would expect that flipping the software media would cause the software itself to flip. But I’ve been surprised at the many ways people misunderstand how computers work.

Software is deeply malleable; it can take many forms. For many folks, digital is magic. Lacking good mental models, they’re unable to interact skillfully with digital systems — unless we design them to meet people where they are.

By establishing clear conceptual models, designers can tweak user mental models in powerful and enduring ways. The result is either a good representation of the system (i.e., one that allows folks to interact with it more skillfully) or one that confuses people — intentionally or not.

Defining a good conceptual model is one of design’s key responsibilities. It requires that we understand how users think about the domain and how they form impressions of the system. Once we do, we can bridge the chasm between user mental models and the system’s conceptual requirements.

Karateka’s inverted floppy disk Easter egg is a facetious example of this dynamic at play.

Today I learned about Karateka’s 37-year-old easter egg - The Verge