Facial recognition, how does it work? At its most basic, the computer processing an image for faces looks for distinct shapes — the edges of a head, eyes and mouth — and then references that against a vast database of known faces to see if the person is one already identified.

But there’s hitch, recently discovered on Twitter: facial recognition software, in its present form, is unable to identify revelers in the Dark Carnival. It turns out that the unique style of facial makeup worn by members and fans of Insane Clown Posse, also known as Juggalos and Juggalettes, is maybe the perfect camouflage for this weird age.

From The Outline:

You might be thinking: “Well, if Juggalos constantly wear this makeup, wouldn’t the facial recognition technology just continually recognize their Juggalo faces?” According to @tahkion [the computer scientist who first spotted the phenomenon and posted about it on Twitter], that depends on the Juggalo consistently wearing the same style of makeup. This problem also assumes that Juggalos wear their makeup all the time — which they don’t. The style is reserved for Insane Clown Posse shows and other special occasions, like the March on Washington.

The Pentagon, like law enforcement agencies elsewhere, relies on facial recognition technologies as a broader part of base security. Bases are large and full of individuals in flux, and outsourcing checks to machines, which can then highlight individuals for human security to follow up with, is just part of keeping bases safe.

What the discovery about Insane Clown Posse makeup reveals, then, is a way for the system to be fooled some of the time. Here’s one hypothetical:

On a base abroad, the Pentagon both relies on local contractors for a lot of the day-to-day function of feeding and supplying troops, but is also worried about insurgents infiltrating the base as contractors. Since the trick of the makeup is that it is only worn sometimes, and it can’t be tracked the same as the un-made-up face, if some of those insurgents had worked as contractors, then launched an attack in makeup, and then retreated, it’s entirely possible they could return to the base with a makeup-free face and the system would be none the wiser.

(Okay, yes, obvious black-and-white clown face patterns would be a giveaway here, but consider instead if it was done with the dark greens and blacks and browns more common to military face paint. A subdued design, following the same application of lights and darks and obscuring both jawline, mouth shape and browline, might be effective in its place.)

Like everything in the offense-defense cycle, it’s unlikely that Juggalo makeup will provide protection from facial recognition software forever. Even with changing styles, different image processing tools that don’t rely on contrast with the background could maybe crack the code.

Given existing overlap between technology built for law enforcement and technology built for military use, a contractor tasked with security around Insane Clown Posse concerts might be able to test new techniques of facial recognition, though given the political activism of the Posse it’s unlikely such surveillance efforts would go unnoticed. And, ultimately, there may be other ways around treating it as a security risk: the paint scheme can fool machines, but infrared cameras can still detect that it’s a human moving about, and humans on the ground can hopefully spot a clown when they see one.