Soldiers being what they are, love to leave behind signs of their passing through. It's become a bit more developed than the "Kilroy was here" of WW2. Here for your amusement is a sample of the art on T-walls in Kuwait, left by units as they waited for flights into Iraq. Our particular symbol for units of the 50th IBCT was the Jersey Devil as seen in the last two photos.
T-Wall is the generic name for concrete barriers that are probably the most remembered and recognised symbol of the war in Iraq and Afghanistan for those of us who were there. Jersey, Texas, and Alaska are the three most common sizes. Compare the size of those states and you can visualize the difference between the height of the barrier. They do save you the trouble of filling and maintaining the equivalent in sandbags.