Before you move forward to look at the illusion with concentration, we would like to warn you that it can also be categorized under trippy illusions, so proceed with caution if you are prone to nausea while concentrating at such images for long. Now, if you see this image, you can find the dots spiraling down towards the center. So what is responsible for this illusion? If you look closely, the dots are drawn in a spiral form. The size is decreasing as you go down. Also, contrasted shades has been used. Together they combine to give the final result that you are perceiving in the image.