It's red when you're amorous. Blue when you're sad. Black when you're downright angry. No, it's not your mom's mood ring, but maybe your next computer.

Apple (NASDAQ:AAPL) filed a patent application back in February that calls for a computer that can "alter its visible appearance" like a chameleon changing the hue of its skin. The envisioned Apple computer would allow the user to alter the hue of its casing through a control panel to match any decor -- or mood -- the user had.

The mood-matching case would be manufactured out of a translucent material to be lit up by red, blue, and green LEDs that produce an image of any RBG value on the surface of the housing when activated. The invention follows Apple's trend of creating colorful desktops, which it began in 1999 when it introduced five "flavors" of its iMac: grape, tangerine, blueberry, lime, and strawberry.

The potential uses for the "MoodMac" are seemingly endless. The case could flash red, for example, for a system error, green when it receives an email, or even pulse different colors while playing iTunes.

The MacObserver website has noted an interesting confluence of applications Apple has made recently. In addition to the "chameleonic" computer, the company has also applied for a trademark on "Morph Pad" in the United Kingdom, as well as a tablet device that looks like an iBook screen without the body of a computer. Taken together, you get an exciting, "movable, musical, and likely video-enabled tablet device that morphs. It may morph in what you use it for; it may morph in where you use it; and it may even morph in appearance."

It would also seem to be a design enhancement that could lower production costs for Apple. Without having to decide which colors will be popular at any particular time, a color-morphing computer would allow for a single design whose ultimate color would be decided by each end user.

Considering the fascination of individualizing wallpaper on the computer's monitor, the ability to customize the color of one's computer case, particularly if it was endlessly configurable, would seem to have mass appeal. Whether or not Apple pursues these applications with any of its forthcoming models remains to be seen, but the potential is there for a unique design that can lower inventory and production costs.

It might not quite be a mood ring, but it just might light up Apple's sales.

Fool contributor Rich Duprey wonders daily when his Windows computer will crash. He does not own any of the stocks mentioned in this article.