Have you ever looked at something, and it appears normal, but after a few minutes of thinking about it, you find it distorted? The brain and eyes are two organs that work together constantly. Two sources feed visual information to the brain:the eyes and the brain's memory of past experience. Usually the information is clear enough, and you have no difficulty figuring out what you 're looking at. Sometimes howeber, the information is faulty. Perhaps nothing in your brain can interpret the clues that come to it. When this occurs your brain comes up with a guess about what it thinks it sees. At this poiint a visual or optical illusion is ocurring. The major tools that make optical illusions possible are lines, circles, and colors.
Lines can quickly give an impression according to the background they are placed in. For example, the green lines in picture number on on the last page appear to be different lengths, but actually they are equal. By using converging lines-- lines that tend toward each other-- the artist creates the illusion of depth. The depth tricks you into thinking the far line, which runs from the floor to the ceiling, must be longer than the near line which does not. Does the structure have two columns or three? Try following the columns fromm top to bottom. It can create a visual problwm. Lines and circles can work to gether to create illusions also.
Angles in lines can distort the shape of a circle, as in example number three. If the off center circle were a coin, would it be able to roll? By the appearance it looks lopsided and you would believe it would not roll. In fact, its a perfect circle. The ancgles formed be the lines coming out of the center of the larger circle confuse you r brain into thinking it sees a irregular shape. Circles placed in smaller circles can distort the eye into