import time
time.sleep(0.1) # Wait for USB to become ready
from machine import Pin 
led1=Pin(2,Pin.OUT)
led2=Pin(3,Pin.OUT)
led3=Pin(4,Pin.OUT)
led4=Pin(5,Pin.OUT)
for x in range(10):
    led1.on()
    time.sleep(1)
    led2.on()
    led1.off() 
    time.sleep(1)
    led3.on()
    led2.off()
    time.sleep(1)
    led4.on()
    led3.off()
    time.sleep(1)
    led4.off()