The points of those geometric shapes line up perfectly thanks to the delta robot arm controlling the light source. The source is a simple LED that can be switched on and off as it moves. A camera is set up in a dark room to keep the shutter open while the arm moves. We’re assuming that all of the light for the stationary objects in this image comes from the LED as well.
[Sick Sad] built the delta bot for just for this purpose. Check out the video below to see, and perhaps more importantly hear, the thing in motion. Seriously, the whine of the stepper motors is pretty awesome on this one.
The delta concept uses a central head on three arms angled down from above. If the LED is also pointed down it won’t light up the hardware and that’s why it doesn’t show up in the image. We’ve seen similar accuracy when using this style of machine for 3D printing. But if you don’t want to build a complicated machine you can try this out with a simple string plotter.