Photographers will often use vignettes to make a 2D image seem more 3D (the goal of any good photographer, regardless of technique). Vignettes can be in the form of filters you put on the end of your lens while shooting. They can be added in during photoshopping. Or for the most fun, they can be found spontaneously while shooting and improvised with. These two shots were taken down the 6" wide barrel of a white lined plexiglass tube. I thought they were a lot of fun, the boys enjoyed it, and the color fade from white to blue/grey was an interesting pop to the composition.