from machine import Pin
from time import sleep_ms
led1 = Pin(2, Pin.OUT)
led2 = Pin(21, Pin.OUT)
led3 = Pin(0, Pin.OUT)
led4 = Pin(4, Pin.OUT)

while True:
 led1.on()
 sleep_ms(250)
 led1.off()
 sleep_ms(250)
 led2.on()
 sleep_ms(230)
 led2.off()
 sleep_ms(230) 
 led3.on()
 sleep_ms(220)
 led3.off()
 sleep_ms(220)
 led4.on()
 sleep_ms(200)
 led4.off()
 sleep_ms(200)