The main attraction of the DePauw Nature Park is its limestone quarry. It is a vast and eery place. After DePauw University took possession of the area, they removed buildings and other environmental damage, and allowed nature to recover.
So one can see the effect of two different forces at once: The enormous momentous force of machines that cut through all that limestone, and the much slower force of plants that take roots again.
This appears to be simple. We know the constituents: water, rock, grass, tree. But then there is weird stuff I don’t know. I will pretend it is harmless.
Maybe Mars looked like this, too, millions of years ago.
The Inner Frame 