from machine import Pin
from time import sleep
led_pins = [2, 4, 5, 18, 19]
leds = []
for pin in led_pins:
leds.append(Pin(pin, Pin.OUT))
urutan = [0, 1, 2, 3, 4, 3, 2, 1, 0]
while True:
for i in urutan:
leds[i].on()
sleep(0.25)
leds[i].off()