As you might expect, these safety notices were dotted around the building and no doubt ignored by 95% of the people in their vicinity unless bored or waiting for someone or something to happen.
It gives a good idea, in very broad terms, of the layout of the site and - of course - the original long-to-physically-manifest question mark design.
Apologies that this is slightly blurred but it was still affixed to the wall. It was obvious whilst wandering around that people had helped themselves to a lot of the signage as 'keepsakes' but it seemed poor form to nick the safety information whilst people were still working on-site. And - knowing me - I would get caught anyway :-)