I had a gap in the wall from where an old monitor mount used to be attached so wanted to make something to cover it up.

The LEDs are controlled by an ESP8622 running WLED, monitor data from the PC comes from Hyperion software. It can be set to a constant color, dozens of set themes, or match the color output of whatever is on my monitor.

The microcontroller sits under the desk and receives constant power, it is the wired to a button on my desk to turn on/off power to the LEDs.

Laser cutter action:

I tried to give it an aged rock/stone appearance using some textured spray paint which actually turned out pretty well. I think some of that doesn't come across well in the photos, but in person it looks good (to me anyway).

LEDs changing color https://imgur.com/a/8CmepDk

How to get WLED running: https://tynick.com/blog/11-03-2019/getting-started-with-wled-on-esp8266/

More info about Hyperion https://docs.hyperion-project.org/en/user/leddevices/