I work a lot with geometrical images. They are shapes based on mathematical instructions.

You can write down the equation of the circle, and imagine the circle in your mind. In your mind, the circle is absolutely perfect. It is absolutely round.

Unfortunately there is no screen, printer, or natural phenomenon that can render a perfect circle. There will always be some particles bouncing out of place. And even if we did somehow manage to create perfection for a brief moment, our imperfect eyes would not be able to perceive it. Our eyes show us a distorted image that our mind corrects.

Geometrical images are conceptual images, they only really exist in our mind.