This is 3D Knob GUI element originally used for rotating the waveform on my turntable its a slimmed down version of that rotating a 3D potentiometer. The output to the screen is scaled down from 0 to 360 normalized down to 0 to 1 range. Feel free to use it as a GUI to rotate a 3D object or use it anywhere you would use a slider.
This emulates the Quartz Composer fog effect, where 3D objects fade to a set color the further away they are from the camera. Thanks to @GeorgeToledo for introducing the solution to use the depth image from Render Scene to Image.