Symmetries catch the eye and can be an important feature of a composition. While this shot may not be much more than a simple clock face on a sunny day, it would be even less without the two clouds either side operating like balancing weights. They also seem to press the composition downwards, adding to the solidity of the building. That's not bad for a public toilet.
Perhaps the sign marks a midway point between two '4's, each of which can only be reached by bicycle. Perhaps the sign is there to indicate that wherever you might think you are, you can go in any direction simply to be somewhere else. Whatever; when you are running a test roll through a camera almost any subject will do.