from machine import Pin
import utime
led_pins = [Pin(18, Pin.OUT), Pin(19, Pin.OUT), Pin(20, Pin.OUT), Pin(21, Pin.OUT)]

while True:
    for i in range(4):
        # Apagar todos los LEDs
        for led in led_pins:
            led.value(0)
        # Encender solo el LED actual
        led_pins[i].value(1)
        utime.sleep(0.5)  # Esperar 0.5 segundos