It's the letter "X" in my Technique Alphabet and today I did a post-processing technique that I've been wanting to try for a while called the X-Ray Effect.
Basically I took a subject that is slightly transparent against a white background (this is the leaf of a bougainvillea plant). Next I turned it black & white, and then inverted the colors. Lastly, I adjusted the whites in the image to give it a bit of a glow. Kind of reminds you of an x-ray doesn't it? ◕‿◕