Our own Mark Frauenfelder discovered the work of Boulder, Colorado interventions-in-nature artist Mike Grab in the best possible way: He happened upon one of Mike’s sculptures, in the wild, soon after its completion. Simply put, Mike Grab balances rocks, one on top of another, in flowing water, with no glue or other means of support apart from gravity itself. Check his online gallery for some lovely photos, or, better yet, if you’re in the Boulder area, go exploring along the waterways and try to find the real thing. [via Boing Boing]