Look at that hand.

That's Donald Trump's hand. And if you look at it closely, there's a distinct thumbprint on it, courtesy of French president Emmanuel Macron at the G-7 Summit.

Yikes! Yahoo has a nice sequential set of photos, including Trump's grimace at the tight grip.

Trump came into office and it became clear early on that he tried to establish dominance by pulling on the arms of the person with whom he was shaking, including Macron.

And after a week of Trump taunting and threatening the other G-7 leaders by tweet, Macron was apparently not having any of it, and left his mark on Trump.

I don't think he'll be the only one before the end of Trump's term in office. World leaders are quickly learning just how to manipulate him.