This is a diffuser for the common 32x32mm 8x8 LED matrix. I never liked how bright those panels are so I decided to make this simple diffuser setup.

There are instructions are simple. Print both parts, the "facade" can be any color you like but the "grid" should be printed in black to avoid light bleeding between pixels. Use the "grid" to cut a square of the diffusing material you like. You can use simple paper, tracing paper or even colored paper if you want a more subtle effect. You sandwich the diffuser between the two parts (you can glue the two parts together is you want something more permanent). And finally whole thing snugly fits on the panel itself.

It is 40x40mm and it has a small lip, perfect for putting on enclosures for DIY projects. Sadly it is not stackable. But it is easy to design something similar for multiple or bigger panels.