Camouflage is a military invention, of course, and it has a long history. U.S. troops first tried camouflage in the late 1800s, when they spread mud on their blue uniforms to blend in with their surroundings. Olive drab and olive green were tried next, until the 1970s, when researchers developed the popular black, brown, green, khaki camouflage. Desert action led to light brown, tan, and green combinations being used for camouflage. Computers jumped into the action in 2004, with a computer-generated randomized green, tan, and grey camouflage that helps soldiers blend in urban, woodland, and desert settings. Research continues, as science and technology attempt to perfect the art of blending in.