from machine import Pin
import utime
 
red = Pin(16, Pin.OUT)
green = Pin(18, Pin.OUT)
blue = Pin(20, Pin.OUT)
 
while True:
    red.value(0)
    green.value(1)
    blue.value(1)
    utime.sleep(1)
    red.value(1)
    green.value(0)
    blue.value(1)
    utime.sleep(1)
    red.value(1)
    green.value(1)
    blue.value(0)
    utime.sleep(1)