G20 Summit 2017 - Subtle signs and nuances

When I first saw this photo (credit to CNN) I was wondering where was Donald Trump. Then I saw him at the edge of the photo, far far away from Merkel unlike the usual spot occupied by past American presidents, beside the host, I was puzzled. Given Trump's big bully antics, he would have elbowed everyone in the way to be right beside the host.

Then I saw a video clip showing how the guests were