Rough gray columns of every size extended to the sky; cottonwood and boxelder trunks formed the walls on three sides. Patches of stinging nettle (I called them burning weeds) sharply jutted between the trees for added security. The ceiling was a canopy of green and brown, branches that softly swayed in the South Dakota breeze, lighting up the room with moving stripes of sparkling sunlight. For years, small feet pattered the ground there, wearing down the weeds to a floor of soft black earth. We called this space in the woods our play house.