They totally failed to stop one guy climbing up the large base of the column in the centre of the square - and he even managed to do a runner and get away with it. (politics.co.uk)
Each ladder is a thin straight line from the centre of one square up to the centre of another square. (newscientist.com)
FYI (if you're wondering why there's a puddle in the centre of the square and warning signs with umbrellas): in the summer, cables are used to create a light rain shower in the middle of the square. (snowtoseas.com)