from machine import Pin
from time import sleep

led=Pin(21,Pin.OUT)
led2=Pin(22,Pin.OUT)
led3=Pin(23,Pin.OUT)
led4=Pin(19,Pin.OUT)

while(1):
    led.off(),led2.off(),led3.off(),led4.off()
    sleep(0.2)
    led.on(),led2.off(),led3.off(),led4.off()
    sleep(0.2)
    led.off(),led2.on(),led3.off(),led4.off()
    sleep(0.2)
    led.off(),led2.off(),led3.on(),led4.off()
    sleep(0.2)
    led.off(),led2.off(),led3.off(),led4.on()