Strange Harvest has a great collection of scans from a book called Masquerade: The amazing camouflage deceptions of World War II that details the ingenious ways that the Allies used camouflage to fool the Nazis, everything from hidden gun-encampments to inflatable tanks and trucks. Shown here: "A US army HQ disguised as a rubbish pile."
Spence's counterfeit docks proved to be good box office. German planes came over periodically to photograph them, but fighter patrols and antiaircraft kept the intruders at altitudes of thirty thousand feet, and at that height it was virtually impossible for enemy cameras to pick up any remaining flaws. On German prints, the Docks looked authentic. Now and then, Nazi long range artillery on Cape Gris-Nez would even lob a few inaccurate shells at the terminus – and whenever these landed the camouflage crews would create suitable 'fire damage' using sodium flares and mobile smoke generators'
(via Plastic Bag)