You have to devise a way to hang a pen-light, or other narrow light source. In this case it was attached to a wire, hung from a rod. Note the camera laying on the floor on it's back? With a wide-angle lens? And a few colored gels? Add a cable release so you don't have to touch the camera and you have your simple set-up.
Difficult to see, there is the camera, on it's back on the floor. The camera is set on "bulb" setting, so you can leave your shutter open as long as you want. You have to play with this, checking your photos to see what you capture. With an f-stop of about 16-22 you will get clear images. There's no way to use autofocus, so you set it on manual and play with the distance between floor and light source.
The circle of light is created by setting your light source in motion. Spin it. Set it in motion in a straight line. Combine your motions. Lights off, you're in the dark except for that single light source (we had more than one set-up so that's why you see a light off to the right, and back). While your shutter is open, and your light source is moving, place colored gels on your lens - switch them if you want more than one color recorded.
There is definitely not a recipe for specific images. You can use something less firm to hang your light from, like heavy string or fish line. This will give you more play as you create your patterns. The idea is to create something different and really play with your camera and settings
And you can see there is really not a vertical or horizontal orientation. Either would work. Blogger seems to think they're vertical:).
The size of your swing dictates how much of your image fills the frame. And you don't know this for sure until after you've taken an image or two. But that's part of the fun! And the use of the gels is guess-work, as well. The photo above was taken using three gels, blue, green and red, and I just switched them out periodically as the swing became less intense.
So, how would YOU use these images?
I'm not sure what I'll do with them, but a couple might look nice enlarged, maybe printed on metalic paper?