My brother’s made one of these things, I believe they are also known as Orbits (in the rave scene). It consisted of 2 of those diamond-shaped keychain LED lights, preferably 2 different colors, key chain portion removed and the 2 ends were zip-tied together and some strong twine was ran through it. One day I was messing with one and due to the forces it generated, on one attempt one of the lights flew off straight into me…almost on par with being shot by an airsoft gun at close range. The second time, the zip tie broke and sent one of the lights skyward probably a good 100 feet and crashed pretty hard on the pavement. That was the end of that.