I saw it slightly differently. I saw the regimented lines within which our children are to play while outside, all around and almost unseen, is the chaos which is nature and the naturalness of the young of any species. But then that is far to complicated a motive for such a simple photo :)
Love the shot. It brings back memories of my recent childhood. Except the playground near the street from my house and in our backyard was made of wood (kind of a death drap my parents began to refer to ours as).
Oh that my childhood were as recent. I had to make do with a swing slung from a tree branch by my father. That and wide fields which changed from green to brown as the seasons revolved where I learned to run and hide and kick a ball and to avoid large horned bulls and nasty slithery snakes.