Monoliths like this one continue to show up all over the Rockies. The refined pillars of stone, or sometimes brick, arrive with no baggage or clear origin. NASA and more clandestine federal agencies have remained closed mouthed on the issue blaming incendiary artists, sculptural anarchists and hermits who live in caves for the odd, vertical monuments. Local residents are warned to check their yards and pastures for intrusions or suspicious behavior on the part of neighbors or livestock.