Basic demo using a WS2812 RGB LED and HD44870 LCD. Seems that Raspberry Pi Pico is in it's early days and library support is a bit limited, but managed to get this working with some sources on the net.
Modes
Set colour value of each individual colour (red, green, blue) using a poteniometer
Using colour value set above, see the resulting colour on the RGB LED.
Very basic colour cycle. Red - 0-255, Green 0-255, Blue 0-255.