WHY DIDN'T WE SEE IT BEFORE?
Apparently if you superimpose 'The Last Supper' with its mirror image, and both are made partially transparent, a barely visible image of a woman holding a child appears. And to think we've missed it all these years.
Just in: If you completely change all the images in 'The Last Supper' you can get this. There's no question Leonardo intended it this way.