If you've ever seen negative afterimage optical illusions, you know that they can be baffling and sometimes quite spectacular. They often involve staring at a negative image for 10-20 seconds and then looking at a blank space. The usual result is seeing what some call a "ghost image" of the negative image, yet it is seen as a positive image (i.e. the way it is supposed to look). These are a well understood retinal phenomenon.
This is a very simple project, yet it is extremely effective. The way that our eyes and brain perceive and interpret images allow for us to trick ourselves in this case. After viewing this over and over, the same effect happens each time. It can be frustrating in terms of trying to figure out why this illusion happens. Ultimately, it is my hope that you will find this helpful, intriguing, and boat-loads of fun!!
Here is a video of the completed project which shows the optical illusion in its entirety: