Neopixel light bar

Articulates +/- 45 degrees, the modular pieces friction fit together, you can glue them if you want. I'm using it to remove shadow lines from my ambilight that are caused by the cables behind the monitor.

Use PET-G for the diffuser to get a better effect and a stronger light (it's usually translucent). Unfortunately i ran out so had to use white PLA. I'll probably just switch to a denser strip.

Using some metalic tape on the internal side walls should also eliminate the hot spots if you only have a low or medium density strip. I've read that the film on LCD screens is really good for this, but it's hard to get.