Touching the thumb and index finger to make a circle, with the remaining three fingers held outstretched, is a gesture that people around the world have made for centuries, mostly in positive contexts.

It is used for several purposes in sign languages, and in yoga as a symbol to demonstrate inner perfection. It figures in an innocuous made-you-look game. Most of all, it has been commonly used for generations to signal “O.K.,” or all is well.

But in recent years, it has also been appropriated for a more malign purpose — to signify “white power.” The gesture has become an extremist meme, according to the Anti-Defamation League.

Now, officials at West Point and Annapolis are investigating whether cadets and midshipmen who made the sign with their hands during television coverage of the Army-Navy football game on Saturday were doing so to express racist sentiments.