from machine import Pin
from utime import sleep

ledVerde    = Pin(15,Pin.OUT)
ledAmarillo = Pin(2, Pin.OUT)
ledRojo     = Pin(4, Pin.OUT)

while True:
    ledVerde.on()
    ledAmarillo.off()
    ledRojo.off()
    sleep(2)

    ledVerde.off()
    ledAmarillo.on()
    ledRojo.off()
    sleep(2)

    ledVerde.off()
    ledAmarillo.off()
    ledRojo.on()
    sleep(2)