Be sure to watch the entire video to see all of the patterns that are created. At the end of the video there are 2 links to watch 2 more versions of the video.
This is a very well known effect that has been performed a countless number of times. I wanted to try and different version by using the black lights and also to add a little production value instead of just simply showing the effect.
The effect works by using a formula that provides the specific length for each string. When all of the pendulums are started at once the patterns will start to form. The pattern resets after about 1 minute. I glued white poster board on the sides of the nuts and used a black light, causing the white to glow.