This 3D printed window decoration celebrates rainbows and the magical material called diffraction grating.

Diffraction grating is a plastic film that is able to act like a prism which separates the wavelengths of light being emitted from a white light source (like the sun or very bright incandescent lightbulbs).

There's actually a pretty good chance you played with this stuff in a grade school science class when you were learning about the physics of how light travels. For this project, it gets used to create a geometric sun-catcher that can hang in a window or on a porch with spotted shade.