import time
from machine import Pin
led1=Pin(21,Pin.OUT)
led2=Pin(22,Pin.OUT)
led3=Pin(23,Pin.OUT)
buzzer=Pin(18,Pin.OUT)
while True:
led1.on()
led2.off()
led3.off()
time.sleep(0.5)
buzzer.on()
time.sleep(1)
led1.on()
led2.on()
led3.off()
time.sleep(0.5)
buzzer.off()
time.sleep(1)
led1.on()
led2.on()
led3.on()
time.sleep(0.5)
buzzer.on()
time.sleep(1)
led1.off()
led2.off()
led3.off()
time.sleep(0.5)
buzzer.off()
time.sleep(1)