At first glance, this image looks like a simple illustration of several striped cats sitting together. But don’t be fooled — this viral eye test puzzle is much more difficult than it appears.

Thousands of people online have tried solving this challenge, and most viewers say they can only find a handful of cats before giving up. The tricky part is that some of the cats are cleverly hidden within the shapes, stripes, and outlines of the larger ones, making them extremely easy to overlook.

Visual puzzles like this test your brain’s pattern recognition and observation skills. Our minds naturally focus on the largest and most obvious objects first. Because of that, smaller hidden details often blend into the background, which is exactly what makes this challenge so difficult.

Many people report seeing only five or six cats at first. Others manage to find a few more after carefully scanning the image from top to bottom. The key is to slow down and examine every corner of the picture, especially around the ears, stripes, and spaces between the cats.

If you think you’ve found them all, count them one more time.

Most people miss at least two.

The correct number of hidden cats in this image is 15.

If you spotted them all, you likely have exceptional attention to detail.