Da Vinci's Code Mistake

For those who had read the Da Vinci’s Code novel, it seems that some meticulous research have been done on art forms, as they are said to have captured the moment when it is made. Some others, have deeper meanings, more than meets the eye.

For example, The Monalisa. Upon close scrutiny, it appears that the horizon in the background differs from Monalisa’s right and left shoulder. Some say that have a meaning. But I think that as good an artist Da Vinci is, he is still human and open to error. How many times that you have to re-do something the next day because it’s full of errors, while it looked perfect upon completion.

I don’t think Da Vinci have CTRL+Z at that time.

But if he does, this is maybe how he painted Monalisa