Wednesday, August 19, 2009
In 1832, a Swiss crystallographer named Louis Necker first published such optical illusions. He created three magic cubes and asked the observers to tell which side was nearest. Different people interpreted the model differently. Here is diagram of the magic cube, also known as the â€œNecker Cube
The color on side makes an observer think that that particular side of the cube is nearest.Another classical optical illusion is given below.
In this image observers are asked to identify the longest horizontal line among. Actually both of the lines are equal in length. Such illusions are called Muller-Lyer illusion.
Another interesting optical illusion was created in 1870 by L. Hermann. He created an image of a grid and asked the observers to count number of black dots. When an observer tries to count the dots all of them seem white, when they are viewed individually. The dots that are not focused seem black. Here is the image.
There are hundreds of other artificial illusions and I am sure you will find most of them over internet. Here is yet another interesting spinning wheel illusion.