from machine import Pin
from time import sleep,sleep_ms
led1 = Pin(20,Pin.OUT)
led2 = Pin(22,Pin.OUT)
led3 = Pin(26,Pin.OUT)
led4 = Pin(21,Pin.OUT)
while True:
    led1.value(not led1.value())
    sleep_ms(200)
    led2.value(not led2.value())
    sleep_ms(200)
    led3.value(not led3.value())
    sleep_ms(200)
    led4.value(not led4.value())
    sleep_ms(200)
    led1.value(not led1.value())
    sleep_ms(200)
    led2.value(not led2.value())
    sleep_ms(200)
    led3.value(not led3.value())
    sleep_ms(200)
    led4.value(not led4.value())
    sleep_ms(200)