Two unrelated people have now demanded explanation for this balance. They were both quite certain that it must be reinforced if at all possible. According to my email an entire high school physics class and their teacher were slightly confounded at how this balance can be real. :D
I admit, this arrangement does look a bit strange.. as in possibly impossible… well.. it is definitely without a doubt a REAL balance. Gravity and rocks ONLY.. this photo was actually taken the next morning.. so the balance remained exactly like this all night.
it may look impossible from a 2-D perspective, but the balancing mass of the arrangement stretches into a non existent third dimension behind the left side of that middle rock… . Also, the top rock is considerably less massive in relation to the middle rock. The top rock, unlike the middle rock, has very little depth. it is more like a flat slab of sandstone i think. Orientation gives a direct look at it’s broadest face.
Here is where it gets a bit more interesting (in my opinion :)
This was a really fun arrangement to play with… The top and middle rock fit together in a variety of counterbalance positions… just by manipulating the middle rock slightly, it could hold the top rock at a variety of levels.. check out the pictures :) Here we can get a sense of just how versatile rock balance can be design-wise.. :)