You’re the Fleet Admiral of the Navy in World War I. Your ships are being sunk at an alarming rate by the devastatingly effective German U-Boat. The traditional camouflage isn’t working because your environment (sea and sky) changes with the weather. What do you do?
Forget about not being seen, that only solves their first problem. Focus on confusing them so they don’t know where you’re going. Then their torpedoes will be shot in vain because they thought you zigged when you really zagged.
British Artist and naval officer Norman Wilkinson had this very insight and pioneered the Dazzle Camouflage movement (known as Razzle Dazzle in the United States). Norman used bright, loud colours and contrasting diagonal stripes to make it incredibly difficult to gauge a ship’s size and direction.
It was cheap, effective, and widely-adopted during the War.