>Then it's a matter of perception. Because I've never seen anything but uniform lines of crosses, in any movie or picture that shows them. Hollywood deforming reality then?
My father was in the US Navy from 1949 to 1956 and he was buried in Jefferson Barracks National Cemetery when he passed away in 2001. The headstones there not in the shape of a cross. The stones can be carved with emblems for the faith of the individual. Here's a Wikipedia link http://en.wikipedia.org/wiki/Jefferson_Barracks_National_Cemetery.
In fact following a link to the Veterans Administration here is a page illustrating all of the available emblems for the stones: http://www.cem.va.gov/hmemb.htm. There are 38 of them, plus 2 for civil war era soldiers and 1 for Medal of Honor recipients.