Virtually everyone has heard of Flat Stanley, the children’s book favorite who has been photographed all over the world. He’s the star of the Flat Stanley Project, which was launched to teach children how to write letters to each other while they learn about geography. Marines and soldiers who served in Marjah, Afghanistan, have their own version of sorts of Flat Stanley, I’ve learned. Key difference: instead of the lovable children’s favorite, they went with Stan Marsh, the foul-mouthed South Park character. Consider the following: Or this: Or this: These photographs come to me by way of the troops who served…