I've written before about how some wedding pictures don't necessarily look like wedding pictures. For me its just not necessary for every picture to include the bride or groom, or flowers, or bridesmaids, or rings or table settings. Sometimes the best pictures happen away from the "action".
I have no idea what this girl was trying to achieve. She was in a world of her own, methodically picking up a chair from the back of the line, carrying it to the front (with some diffculty), placing it in line and then repeating - over and over again.
I think I watched her do it at least 10 times. I had to wait until she'd done it enough times that were enough chairs to fill the frame, and that when she got to the front of the line she wasn't obscured by the strapping that runs through the middle of the picture.
It was a case of watching what was happening, pre-visualising what the picture would look like, and then waiting for the right moment to capture it.