not only is there horizontal symmetry, with the subtle reflections of clouds and mountains and figures in the water, but also there's the pair of boats in the background mirroring the pair of girls facing each other in the foreground both on a vertical axis. i'm so glad i caught that moment.
this picture would be kind of trite if it wasn't for all the symmetry, and the long shadow in the foreground, and the guy to the far right. at first i was a little disappointed that that figure was sitting down, but now i think it adds interest. i think the fact that he's apart from the group and not a subject in the photo being taken makes him the main subject in this meta-photo, despite how highlighted the central figure/focal point is.