I started with one of these flashingblinkylights.com/Light-Up-Pens/rainbow-light-pen-with-spiral-brbfont-colorfff000call-for-details-on-free-1-color-imprintingbfontbr-sku-no-10241.htm

It's a pen that gives off different colors of light. I hung the pen from a string and put it into motion and took a 10-15 second exposure shot of it with a newer digital camera. In some of the shots the camera was stationary and in others, I moved it during the exposure.