Simple diffusers for the common approximately 65x65 mm rigid PCB 8x8 WS2812B matrix modules.

The modules don't quite have a square pixel pitch so it's fudged a bit for an 8.5 mm square pixel pitch.

Fit is snug so will likely require some flexing of the walls to push the modules past the retaining tabs.

Diffusers for single modules and 2x1, 2x2 and 4x1 modules.

FreeCAD source file included if you want other sizes.