Found this on the Spin.co.uk blog, where you can find nice graphics.
I love this creative use of the pavement to show people the way, you could say that the graphic could not be clearer, e.g. it does what it says not the tin! I particularly like the way that individual markers can be combined to develop a language of direction.
However if you are looking around for a sign, you might miss it. In my experience most people look for signs at the height of the object that they want to find, though I bet someone has done the research that will prove me wrong, another bit of knowledge to join the list of issues to check out.