This optical illusion, which went viral on Twitter, racked their brains 3.5 million people

The optical illusion looks like two 3D cubes are moving in space, but in reality they remain stationary. An animation posted on Twitter by Science Girl shows two cubes next to each other against a blue background.

The colors of the cube lines change from black to white in a circle, and the cursor in the center of the cube points in different directions, giving the impression that the cubes move up and down, rotate and grow in size.

But in reality they are motionless.

The illusion, which has been viewed over 4 million times on social media (3.6 million on Twitter), is caused by a phenomenon called the “Reverse Phi Illusion.” This phenomenon is characterized by the fact that the change in light – as in the case of lines that change color from black to white – deceives the mind, making it think that something is in motion, although it is not.

The illusion is so well executed that many skeptics could not believe that the cubes remained in place and tried to refute the trick with video editing.

The reverse phi illusion is a phenomenon that arises due to the peculiarity of vision that both humans and animals have, and even insects, such as flies. If we see that a bright point appears to the left of us, and another to the right, we perceive it as movement. That is, the sequential inclusion of light sources is perceived by a person as the movement of light.

If a dark object becomes light, the brain interprets this as “moving away” from the object. When two points repeatedly pass from light to dark, we perceive it as movement.

In 2011, researchers from Stanford University showed that this phenomenon arises from the laws of vision of movement. “This is the main effect underlying the fluid motion we see in movies and animation,” the scientists explained.

Users were particularly confused by the cursors in the center of the cubes. Many have tried to use them to refute the Science Girl message, writes the Daily Mail.

One commentator wrote: “This is fake, the cubes move even when the arrows are closed.” Another said, “Hide the arrows and they still look like they are moving.”

However, the secret of this illusion lies not in the cursors on the cube, but in the color used to highlight the cubes: black and white.

Some people have correctly identified how this trick works.
One of them writes: “To all people who think that these figures are moving: NO, DO NOT MOVE. Take a piece of paper and check every line: they DO NOT move one iota. “

Another adds: “Place the mouse cursor on one of the corners of the cube and look only at the cursor and corner. The corner never moves away from the cursor. “

People who believed in the truth of the illusion were shocked at how our perception works. “I thought Schrödinger’s box was difficult. In this scenario, there is not even a cat … and yet somehow it is even more difficult to accept, ”said one of them. “This is the craziest thing I’ve seen on the Internet. And I saw quite a few … My roof was blown off, ”wrote another.