When I was a child I lived in Sunbury on Thames, where the pavements are made of concrete slabs. While they are easy to install, and even easier to rise again, if maintenance and repair work is deemed necessary, they do have one major drawback they crack easily. Take a walk around any built-up area, where these slabs are used, and you will see what I mean. You will see cracks everywhere. Most people going about their daily business never notice these failings, beneath their feet. And if they did happen to notice the cracks, I am sure they wouldn't give them anything more than a passing glance. I, however, gave them a lot more attention than that. I saw each and every one of these cracks, be they chips off the corners or giant earthquakes splitting entire slabs in two, for what they were a golden opportunity to run with the precision of an Olympic athlete.