Simple LED diffuser for brass embedded LEDs for staircase night light. The design is staggered so that the core peeks out from the shell's top level.

Print in translucent/transparet PETG, outer shell black ABS. Core shall be printed with 20%-30% infill grid type to ensure light distribution. Even higher infill % might improve the diffusion effect. Two perimeters, at bottom only one perimeter is recommended. Bottom layer best results co-centric pattern. (Those on photos are just 45 degree lines - I will re-print them later)

Update added a STL for closed bottom to prevent light leakage

Optimized for 0.4 mm nozzle. Cad file for your tweaking…

(I am planning to make flat top version later, and also round ones, flat and round are only step files now)