from machine import Pin
import time
merah=Pin(15,Pin.OUT)
kuning=Pin(16,Pin.OUT)
hijau=Pin(17,Pin.OUT)

while True:
    merah.on()
    time.sleep(3)
    merah.off()
    Kuning.on()
    time.sleep(3)
    kuning.off()
    hijau.on(3)
    time.sleep(3)
    hijau.off()