Case: - I decided to go visit the museum today. It was a great day outside so I walked. Well, wouldn't you know it! When I was crossing the street I tripped over this really small pebble and was sprawled out along the side of the road.
My right elbow skidded across the pavement and came to a stop against some kind of cement restraint at the side of the road. What stopped me from skidding another quarter mile down the road?