Synopsis: This curriculum unit will make a significant contribution by exploring how optical illusions teach us about how our eyes and brain work together to see. We live in a three-dimensional world, your brain gets clues about depth, shading, lighting and position to help you interpret what you see. When you look at a two-dimensional image, your brain can be fooled because it doesn’t get the same clues. Optical illusions are extremely important for everyday life, people use them for jobs such as pilots, fashion designers, architects and landscapers. Optical illusions also known as visual illusions involve visual deception. The arrangement of images, effect of colors, and impact of the light source all contribute to the misleading nature of visual effects. When we view a visual illusion, we may see something that is not there or sometimes we do not see something that is there. There is a disconnect between perception and reality. Visual illusions prove that the brain could fail to re-create the physical world. Illusions are also explained as mind games. Scientists are fascinated by illusions because by figuring out how the eye and brain can be tricked; they can better understand the normal workings of the visual system.