Mr Brook has seen some work by a photographer / artist called Jiri David. He did a project called 'Hidden Image' where he tried to find out how symmetrical people's faces were.
Click on his name to go to his website.
"We had to take a photograph of ourself, turn it into greyscale and then crop it into two even halves. Using Paint Shop we then mirrored each half of our face and merged them together to make two new hidden images. You can see my new images here."
Here are some more of Jiri David's examples.
The hair is particularly interesting!