from machine import Pin

import time


red    = Pin(16, Pin.OUT)

yellow = Pin(17, Pin.OUT)

green  = Pin(18, Pin.OUT)


def set_lights(r, y, g):

    red.value(r)

    yellow.value(y)

    green.value(g)


while True:



    set_lights(1, 0, 0)

    time.sleep(2)
    set_lights(0, 0, 1)

    time.sleep(2)

    
    set_lights(0, 1, 0)

    time.sleep(1)