from machine import Pin
from time import sleep

led = Pin(10, Pin.OUT)

# function
def countdown():
    counter = 5
    print("Countdown start")
    while counter > 0:
        led.on()
        sleep(.5)
        led.off()
        sleep(1)
        counter = counter - 1
        print(counter)

# function
def forloop():
    counter = 0
    print("For loop start")
    for i in range(0, 5):
        i = led.on()
        sleep(.5)
        i = led.off()
        sleep(.5)
        counter = counter + 1
        print(counter)

while True:
    countdown()
    print('Countdown done!')
    forloop()
    print('For loop, done!')