I got the glass block, base and decals from A.C.Moore. The snowy inside is the A.C.Moore shoping bag from buying the other parts.
At night the different colors show very well
These RGB leds create the the different colors by having a PWM signal applied to the R, G and B connections.
This is the controller a Raspberry PI Zero, I cut a hole for it in the bottom of the base and this runs a python program producing the PWM for leds.
Back view of base, showing power supply entering the base.
This is another lamp that I made. I raised the leds about an inch off the base so that the lights are not visble through the bottom edge of the glass block. In the other lamp I just stick a small piece of paper in front of the leds.