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 colours, as seen in this colourised photo: