Spring is here, part III

The surface of Sweden has changed. That's a fact. If you happen to fly by this country in spring, or summertime, you will notice something odd. Something you didn't use to see a few years ago. In every suburban, picked fenced neighborhood, there are strange circles. Landing zones for UFO's? Helicopter platforms? Nah. Just one of the most certain signs of the season of neverending light: the trampolines.