The thing about illusions is, they trick you even when you know why. Understanding that you are making a visual error doesn’t help you to correct it.
Below are some examples of illusions. There are also some visual stimuli where the figure and ground swap depending on which part of the picture you focus on. Some of the visual stimuli below promote more than one possible interpretation, either through the figure-ground swap or because they are ambiguous in some other way.
To watch the video below, you will need to click on the link and go to Youtube.