Imagine if footsteps piled, tangibly, one on top of the other! We'd suffocate with history. We'd be born on top of them. We'd fall into the spaces between. Everyday, we'd be sooo tired just trying to push our way through! I guess we couldn't really build anything on top of them. Footstep shovelers would have to work 24/7 just to clear the way for the next minute.