During WWI, German U-Boats were alarmingly effective at sinking allied warships and transport vessels alike. But since a ship couldn't exactly be cloaked, Norman Wilkinson, British artist and naval officer, developed another method nicknamed razzle dazzle.
U-Boats were effective but simple—they shot torpedoes, not directly at ships, but where they estimated a ship would end up once the torpedo got there. Razzle dazzle was an artistic countermeasure, less camouflage and more just a highly confusing pattern meant to make judging a ship's direction and size more difficult.
What you won't see in the lead shot was that these ships weren't just striped—they were covered in an array of colors, as seen in this colorized photo: