Unfocus your eyes as you stare at the following image. Force the blurred white dots to overlap until they come back into focus, one atop the other. In the resulting 3-D image, which row is farthest back? Which jumps farthest off the page? Our brains usually meld the two, slightly different images that come from each eye to create the appearance of three dimensions. By “layering” one dot atop another, you provide the brain with two slightly different images, which combined look three-dimensional.
Crocodile Tears
The fifth cranial nerve controls the face’s mucous membranes: snot, tears, saliva, etc. And when this cranial nerve is damaged, liquids can go awry. In the neurological disorder known as crocodile tears, patients cry when they eat—they produce tears instead of saliva.