“Appearances can be deceptive”- A lot of phenomena can be effortlessly explained by this saying. Be it the oldest performing art – MAGIC, virtual reality or interpreting a random cloud pattern in the sky to be something meaningful like a man’s face, rabbit or whatever. The last phrase is an example of what we call the ‘optical illusion’. Optical illusion is a term that explains how dishonest your eyes to you are. It is the difference between what we see and what really exists. In other words, our eyes perceive and send misleading (wrong) information to our brains. As a result, we see and believe (at least for a moment), what could not be plausible since eyes are the most trustworthy sense organs.


Despite its natural occurrence, various optical illusions are unceasingly being created. Creating optical illusions is now a form of art. Though optical illusions are created for recreation, they can really tease one’s brain and test the friendship brain’s friendship with the eye. Many famous optical illusions that exist today have been designed well enough to fascinate and fool your eyes and brain. Here are some of the needles from the haystack:


The Ames Room Illusion:       




What if two people of equal height get into a room and abruptly we see a drastic difference in their heights? Sounds impossible…but the AMES room makes it possible through its unique construction. An AMES room looks like a regular rectangular room to naive viewers. But the real shape of an Ames room is a six sided convex polyhedron. This elucidates the height differences we see in those people.



The Muller – Lyer Illusion:               



Many people might have come across a video showing the above picture with the question “Which line is longer?” and gotten exasperated by the answer that all of them are of the same length. It is nothing but a product of optical illusion named as the ‘Muller–Lyer Illusion’. If we draw a straight line through the arrows at their end points, we see the truth!


The Kanizsa Triangle Illusion:                                 



The Kanizsa triangle is another classic example of optical illusion. Here is a white equilateral triangle that can be seen explicitly although it has not been actually drawn. It is just the space between the patterns that forms a triangle. The white triangle seems brighter than the background since it is outlined by the black circles and the triangle.


The Impossible Triangle Illusion:                   



Also known as the Penrose triangle, this is yet another optical illusion gifted by the tricky triangle family. This triangle seems to be flawless when viewed from a particular vantage point. But when we view it in a slightly different angle, we would come to know that this triangle cannot possibly exist. This optical illusion plays with our eyes’ perception of objects. The Penrose triangle can be drawn in two dimensions but cannot be formed as a solid three dimensional object.


The Ponzo Illusion:                              



This is a familiar optical illusion that we see in every pair of railway track. In the above picture, we could see that the pair of railway tracks is converging as if meeting at a particular point. This illusion is based on the fact that human minds judge an object’s size from its background.  However if we draw horizontal lines at the nearer and farther points of the tracks, it can be clearly seen that both lines turn out to be of the same size. Again, perception plays a vital role here.


It can be derived that the above optical illusions employ simple factual understanding of psychology and perception. As pointed out earlier, the role of optical illusion is remarkable in the field of magic. Optical illusion with a pinch of skill and distraction can do wonders. So the next time, be more cautious in trusting the greatest magician – ‘your eyes’.


Written by Nirupama S, Third Year, CT department.




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