from machine import Pin
from time import sleep_ms

led01 = Pin(18, Pin.OUT)
led02 = Pin(19, Pin.OUT)
led03 = Pin(21, Pin.OUT)
led04 = Pin(22, Pin.OUT)
led01.off()
led02.off()
led03.off()
led04.off()
while True:
  sleep(0.5)
  led01.value(not led01.value())
  led02.value(not led02.value())
  led03.value(not led03.value())
  led04.value(not led04.value())
from machine import Pin
import time

led01 = Pin(16, Pin.OUT)
led02 = Pin(17, Pin.OUT)
while True:
  led01.on()
  led02.off()
  time.sleep_ms(500)
  led01.off()
  led02.on()
  time.sleep_ms(500)