I'm a retired engineer who lives on a sail boat. I'm tired of frequent replacement of my flags that tatter rapidly as they flap in the wind. I would like to suggest this as a challenge to other engineers. How can we design a tatterproof, flexible and affordable flag? I added the word flexible, because the obvious design of a rigid flag would have been used for millenia past if it satisfied flag customers. Therefore, I reject rigid flags as a solution. Good engineering usually starts with good descriptions of the physics. They tatter when they flap but why do they flap? Wikipedia has a non-explanation here. Physics forums has a whole lot of non-explanations here. Physics.apps.org has a very interesting explnation here. It says, "Since gravity tends to collapse a flag along its diagonal, while wind tends to stretch it out, the wavelike motion of folds in a flag is at an oblique angle to its length." That's ingenious but I'm sure that flags flap and tatter when hung horizontally as well as hung vertically. Then there is the related but separate topic of tattering as distinct from flapping. I can't find any scientific literature on that at all.