It takes a few moments to see the spotted jaguar slinking through the dense, sun-dappled jungle scene projected onto a wall inside the International Spy Museum in Washington, D.C. Soon after, the projection changes to a snowy forest where it takes even longer to notice one—no, two—human figures nestled among bushes and rocks, obscured by gravelly full-body suits and skin-concealing tactical gear. The hidden figures, animal and human, are quintessential examples of the subject of Camouflage: D...