import digitalio
import board
import time
led = digitalio.DigitalInOut(board.D13)
led.direction = digitalio.Direction.OUTPUT
k = 0
while True:
    led.value = True
    time.sleep(0.5)
    led.value = False
    time.sleep(0.5)
    k = k + 1
    if k == 3:
        k = 0
        time.sleep(0.5)