Tough to see, I know, but you're going to have to trust me on this. The definitive, setting-the-art-historical-world-on-its-ear link is the victory sign being flashed across the centuries by both bambinos and both Nixons.
Finally, as a testament to the lengths to which I will go in pursuit of knowledge, the top left Madonna and Child is in the Bargello Museum in Florence, which is a strict no photo zone. The reason the composition of that photo is just, um, a tad off, is that I shot it while holding my camera at my hip while three museum guards stood about 10 feet behind me. Apparently I'm far better at shooting from the hip rhetorically as the above was my best effort among:
I imagine the guards, if they were paying any attention at all, were starting to become a little suspicious upon my fifth or sixth pass by this piece, attributed generically to an Umbrian artist, in a museum that also included works by Michelangelo, Donatello, and Giambologna.
In any case, look for my paradigm-shifting article in a 2013 issue of Art Bulletin.