from machine import Pin, ADC
import utime

red = Pin(16, Pin.OUT)
green = Pin(18, Pin.OUT)
blue = Pin(20, Pin.OUT)
potentiometer = ADC(Pin(27))

rgb_list = (red, green, blue)

while True:
    for led in rgb_list:
        led.value(1)
    rgb_list[potentiometer.read_u16()//22000].value(0)
    utime.sleep(.01)