As a suggestion by @twistergirl , I applied a similar processing technique that I had done to convert my icicle into a dagger with a drop of blood. This time a full moon/tree silhouette became a series of arteries and arterioles, with an ominous black growth of sorts. Not pretty.
But wow -- how effective is that! Seriously, how do you turn trees into the inside of a heart? Just think how much money the science textbook people can now save in getting good photos without having to go into surgery.
