So you use your kite's thread to cut the thread of other kites. Last kites flying at the end of the festival "win." The threads are often coated in glass dust to make it easier to cut the threads of other kites. You have to be careful because you can injure yourself or others if you're not careful.
We erect towers for people to fly their kites above the rest of the festivities so people can still mingle and watch from below.