Gentleman of the jury, let me explain. A pure mare’s nest. I am a man misunderstood.
Devising marking systems (signs & etc.) which can be easily understood by anyone, anywhere, and in any language, is never going to be an easy task. Now imagine that on top of this, the systems have to remain intact and effective for the next 10,000 years. Specifically to discourage inadvertent intruders at a large-scale nuclear waste repository.
Just such a daunting task was evaluated by two teams co-ordinated by the US Sandia National Laboratories in 1992. They produced a 351-page report detailing their findings: Expert Judgment on Markers to Deter Inadvertent Human Intrusion into the Waste Isolation Pilot Plant [PDF | 20MB].
oil on canvas { Johannes Kahrs, Untitled (four men with table), 2008 }