from machine import Pin
import time
led1 =Pin(2,Pin.OUT)
led2 =Pin(3,Pin.OUT)
led3 =Pin(4,Pin.OUT)
while True:
    led1.toggle()
    time.sleep(0.1)
    led1.toggle()
    led2.toggle()
    time.sleep(0.1)
    led2.toggle()
    led3.toggle()
    time.sleep(0.1)
    led3.toggle()