import time
from machine import Pin
pin5 = Pin(5,Pin.OUT) 
pin18 = Pin(18,Pin.OUT)
pin19 = Pin(19,Pin.OUT)
pin21 = Pin(21,Pin.OUT)

i = 1
while i <= 10:
    print(i, end = ', ')
    i = i + 1
    pin5.on()
    print ("LED ON ")
    time.sleep(0.5)
    pin5.off()
    print ("LED OFF ")
    time.sleep(0.5)

    pin18.on()
    print ("LED ON ")
    time.sleep(0.5)
    pin18.off()
    print ("LED OFF ")
    time.sleep(0.5)

    pin19.on()
    print ("LED ON ")
    time.sleep(0.5)
    pin19.off()
    print ("LED OFF ")
    time.sleep(0.5)

    pin21.on()
    print ("LED ON ")
    time.sleep(0.5)
    pin21.off()
    print ("LED OFF ")
    time.sleep(0.5)