Visual acuity test: here are 16 circles, are you able to find them?

A somewhat dizzy image, which looks like a bar code, but has become viral in a few days. Within this amalgam of gray, black and white lines and rectangles, there are also circles thanks to an optical illusion.

This viral puzzler was released by artist Nicholas J. Johnson, who shared it on Facebook telling it took half an hour to find all the circles.

The image became very popular on Facebook, calling the users to participate. At first sight, you can only see horizontal and vertical lines, and rectangles, however, the goal of the challenge is to find circles. Therefore, the first thing that is usually done is to look for some curved line inside the rectilinear image.