Fear not (!), this isn't attack of the giant chairs, but merely testing AR technologies around Oxford earlier today. We are able to take objects (chairs or buildings) into AR with nothing more than a smartphone.
This is all pretty clever technology. The models react to the environmental lighting to help them sit in the environment they are placed within.
Positional tracking is excellent, so the model sticks locked to the floor.
Design testing, model checking, marketing buzz...the possibilities are endless.