All of the edges in this image are straight and either horizontal, vertical, or at a 45° angle.  Does it appear that way to you? Edit:  I just also noticed that if you move your scroll bar up and down when viewing this image it appears to have some motion elements to it.

Do you see a spiral in the image below? There is no spiral.  This drawing consists of a series of concentric circles.  This illusion, called the Fraser spiral was discovered by British psychologist James Fraser in the early 20th century.