I've been reading Haynes "workshop manual" on the M1 Abrams (yep, another one!) and stumbled across a funny "easter egg" which I'm amazed got past the editors. On page 124 there's a distant photograph of one of the authors standing out of uniform in front of his tank during the Gulf War. And I mean
totally out of uniform. You can't actually see anything, but it's pretty obvious the guy is a bit "scruffy" in well..."certain places." You get the picture.