A fun exercise
The first shot is that of a 400 year old courtyard wall in St. Augustine. It's made primarily of compressed coquina shell blocks. A staple of construction back then.
This second shot is the result of me throwing some of my mysterious rust elixir on the image. I didn't know what to expect......got slap blown away.
I guess I had better safely stash this elixir away. I wouldn't want it to get in the wrong hands.