This is a lamp I designed from the excellent work of two previous designers. I recommend printing the front part in white so that the light will shine through. Two inside middle sections are provided, a complete one and one with a 28mmx28mm cutout in the middle. The one without the cutout allows you to cut or drill out to fit whatever you are using as a light source. The inside middle file with the cutout section was what I used to fit the light source I had (a color-changing led light).

I recommend using aluminum tape to better reflect the light. Also, you can superglue the inside middle and front on to make sure they hold. I painted the black and red parts on the front in acrylic paint and then used a sealer.