Pretty cool ! Looks as if they ran out of guys for the head, torch, etc. I might send it to someone on active duty and, who knows, they may want to do an updated version.
Taking a longer look, I guess the upper areas may be soldiers who intentionally have those areas shaded differently. Sort of like the people holding various colored placards at football games to spell or represent something.
I ran across this very same picture while surfing the www. I'm glad Gypsy posted this picture, isn't it awesome? Well, I just ran across another website, talking about the 2 photographers who traveled the US taking such pictures of soldiers and bases. Enjoy!