16 squares (8 blue, 8 white) in a checkerboard pattern make up November, which stands for "N" in the signal flag alphabet. It must have been miserable to be the guy who had to make this one by hand. I bet the whole time he was thinking "Why didn't they just make it 4 squares like Lima?!" I'm thinking the same thing man.
November means negative, which makes sense. I always appreciate an alliteration after all. You can fly it if you disagree with or can't comply with another ship's request. For example, if someone flew a cubist pacman at you but your rudder is stuck to starboard, you can fly this back. Or if someone asks you to do something and you feel like being a petulant child.
When flown with Charlie ("C", Affirmative) the two form a distress signal.
Check out the rest of our Signal Flag explanations!