import machine, utime

led_red = machine.Pin(15, machine.Pin.OUT)
led_amber = machine.Pin(14, machine.Pin.OUT)
led_green = machine.Pin(13, machine.Pin.OUT)

while True:

  led_red.value(1)
  utime.sleep(5)
  led_amber.value(1)
  utime.sleep(2)
  led_red.value(0)
  led_amber.value(0)
  led_green.value(1)
  utime.sleep(5)
  led_green.value(0)
  led_amber.value(1)
  utime.sleep(5)
  led_amber.value(0)