A warning sign that reads “infected” or “polluted area”. By what, however, remains the question. Though it must have been a common, rather casual occurrence to the humans involved, to warrant the installation of a hinge. A cattle farmer, flipping the sign up to indicate a stable or meadow having been infected by the newest cow craze. A forester, warning unsuspecting hikers of dangers hiding in the tall grass. Or a researcher in a laboratory, informing other of a routine safety hazard. Routine danger ahead.