from machine import Pin
from time import sleep

leds=[
    Pin(0, Pin.OUT),
    Pin(1, Pin.OUT),
    Pin(2, Pin.OUT),
    Pin(3, Pin.OUT),
]
    


Tiempo=1

while True:
    #Izquierda a derecha
    for led in leds: 
        led.value(1)
        sleep(Tiempo)
        led.value(0)
    #Derecha a izquierda
    for led in reversed(leds): 
       led.value(1)
       sleep(Tiempo)
       led.value(0)