alt Hacker Newsfor the curios or those that skipped over it:
"Black Rock City is only allowed to return to the playa each year if it passes a strict post-event inspection from the Bureau of Land Management (BLM): No more than one square foot of debris can remain per acre (0.23 m²/ha)."
K, but what’s a square foot in metric? And percent would be better here. Or per Mille to be annoying.