Chances are that at some point when searching Google, purchasing concert tickets, or signing up for a forum, you’ve had to click a few boxes to confirm your humanity. But while these CAPTCHA tests are usually meant to keep robots out, one website is welcoming them in.

The conceit of Humans Not Invited is essentially a reverse CAPTCHA. Visitors to the site are greeted with a vision test not unlike the ones you’ve done before, but instead it’s filled with seemingly indistinguishable blue and gray blurry boxes. When I tried, I was prompted to “select all squares with selfie sticks.”

Most humans, like me, will fail to decipher the hidden selfie sticks and will be shown a message that says “YOU’RE A HUMAN. YOU’RE NOT INVITED.”

To the human eye these boxes appear indistinguishable, a specially programmed bot can spot out the correct image simply by identifying a handful of pixels, according to the project’s creator, Damjanski, (his real name is Danjan Pita).

“It’s real images that we blur via an algorithm and then serve up to the captcha,” Damjanski told me in an email. “So for example when the captcha asks you to select each square with an Ewok—there are some blurred Ewoks in that captcha. We also have a program changing always the image titles so people can’t trick it by checking the names of the image files.”

Damjanski both expected and wanted people to find a way to beat the test, and created a secret bot room in part as a way to engage with the programming community. The internet artist dropped the site on Hacker News last week. Not long after, people had found a way to create bots to bypass the test.

Since then, Damjanski said he and a team of two other friends have been reevaluating and toughening the challenge.

“We constantly update the algorithm on different variables like for example how many pictures it serves or in another case how it blurres the images,” he said.

The bots that do gain entry live on as a list of growing list of published IP addresses. According to Damjanski, more than 30 bots have made it in so far. If one does gain access to the locked robot room, they will be greeted by the words, “Welcome! You are not a human.”

The test isn’t perfect. Redditors have said that some of them have been able to get through the challenge without a bot at all, though no one at Motherboard was able to pass the test. If you like this sort of thing, it's worth checking out r/totallynotrobots, A PLACE TO HANG OUT WITH FELLOW HUMANS.

The internet artist said he did not have any set timeline for the project and plans to continue updating the algorithm as people find more creative ways to breach the test. Damjanski said he sees these projects as “an online performance.”