Every now and then I check the visitor logs for this blog to see what brought people here. Sometimes they have looked for something in a search engine, and I run the same search to see what else would have come up.
When I ran a search for which my photo question of the blinded sphinx moth came up very high, I discovered fascinating pages (the best summary I found is here) about dazzle painting -- art used to camouflage warships in WWI.
They had figured out that it was not possible to hide a ship on the surface of the ocean, but they could make it very difficult for a U-Boat commander to target the boat. By the use of shading, broken diagonal lines, and other optical illusions, they could conceal from an observor the orientation, direction, and speed of the ship.
So what was a U-Boat commander to do? Step away from the periscope, shut his eyes, and "Use the Force, Luke."