Cerol is old story. You can do it at home. Ground glass and glue. That’s all you need.
Kite fight is almost a tradition in Brazil. The real masters of kite fighting are capable of even capturing the enemy’s kite, wrapping it their own kite’s tail (called rabiola).
Now, when they do this near a highway, the razor sharp line can fall into traffic and cut through the necks of people in bikes. I had a line crossed in front of me once. I was in a car and the line wrapped on my mirror. I didn’t stop there because I thought it was dangerous. When I finally did, the line was embedded into the mirror’s casing, having cut through the plastic.
Another thing that can cause death related to kites. Kids love running after the cut ones. And they’re usually looking up, not sideways when running. So, being struck by a car is easy.