from machine import Pin
from time import sleep

led1 = Pin(0, Pin.OUT)
led2 = Pin(1, Pin.OUT)
led3 = Pin(2, Pin.OUT)
led4 = Pin(3, Pin.OUT)
led5 = Pin(4, Pin.OUT)
led6 = Pin(5, Pin.OUT)

while True:
    for i in range(0,6):
        led = Pin(i, Pin.OUT)
        led.value(1)
        sleep(0.5)

    for i in range(5,-1, -1):
        led = Pin(i, Pin.OUT)
        led.value(0)
        sleep(0.5)