We have studied about observations and using the five senses to make careful observations.
Illusions occur when one or more of our senses has been fooled.
Our eyesight is by far our most important sense, and so optical illusions are the most common type . Click here to see how this can happen. Now that you know a little about illusions, click here to view some more. Optical illusions can be classified into many general categories. One of these is called an afterimage.