Wave a high-powered laser around fast enough, and the human eye will perceive an image in the light trail left behind. That’s how laser projectors that cost thousands of dollars work, but it’s also how this cheap, 3D-printed plastic contraption turns a simple laser pointer into a full-on light show.
Source: Gizmodo – This 3D-Printed Contraption Turns Laser Pointers Into Trippy Little Light Shows