sort of CGI

I know everyone is going to say this isn't CGI but i think it is as i'll explain now.
I had to show light traveling throung lenses for an astronomy animation so i drew it all up and did the animation. the problem was during the animation some paper slipped and it showed the table underneath for a few frames. so i opened a photo (that hadn't got the table showing) on paint and copied the top part of the photo and pasted it onto the photos with the table showing.
here it is. It is only 10 seconds. I don't know how much of that essay was understandable so i will be amazed if anyone understands it.