The entire graphic is made up of horizontal and vertical bars of various lengths - all straight lines. So, can you spot all 16 circles within this illusion?
Optical illusions are always fun to play with, but some can be particularly challenging on the old eyes and brain. It's fascinating to see how different people process them and how quickly or slowly - or sometimes not at all - people see things that aren't really there or see images hidden within other images.
It's called the coffer illusion and was created by Stanford University psychologist and vision scientist Anthony Norcia. The image is made up of a pattern of black, white and gray lines of various shades that create the illusion of rectangles. It's easy enough to see the rectangles.
As you cast your eyes upon the seemingly straightforward pattern, you might be forgiven for assuming that it's composed solely of linear elements. However, the brilliance of the Coffer Illusion lies in its ability to hide a series of perfectly arranged circles within its intricate design.
One way to see the circles is to focus on the vertical bars between the rectangles. For some, that makes the circles suddenly pop off the screen. If you can't spot them, see below.
According to an explanation from a professor and student from the University of Sydney, the reason we have a hard time seeing the circles at first is because of our brain's strong tendency to identify objects in what we're seeing. The lines come together to form edges, contours and shapes, and our brains fill in the objects.
"For most people, the grouping into rectangles initially dominates," the authors write. "This may be because rectangles (including the ones we see in door panels) are often more common than circles in our daily environment, and so the brain favours the grouping that delivers rectangular shapes."
The Coffer Illusion, with its hidden circles, not only showcases the art of visual deception but also underscores the playfulness of perception. It invites us to question our assumptions and embrace the delightful surprises that emerge when we look beyond the surface.