from machine import Pin
from utime import sleep

red = Pin(21, Pin.OUT)
green = Pin(19, Pin.OUT)
blue = Pin(18, Pin.OUT)


def enable_red():
    red.value(1)
    green.value(0)
    blue.value(0)

def enable_green():
    red.value(0)
    green.value(1)
    blue.value(0)

def enable_yellow():
    red.value(1)
    green.value(1)
    blue.value(0)

while True:
    enable_red()
    sleep(10)
    enable_yellow()
    sleep(2)
    enable_green()
    sleep(10)
    enable_yellow()
    sleep(2)