When we stumbled upon these piles of rocks at the waterfront in Sausalito we thought that for sure they must be magneted or glued or somehow stuck together.
We were wrong.
We soon noticed the man who was building them, and watched him pick up rocks at random, inspect each one that he picked up, and then balance them ontop of eachother. He'd put a rock ontop of another one, and then walk all around it looking for weaknesses, and then whack at the tower with a small stick - but quite hard - to make sure that it was sturdy enough.
