from machine import Pin     
from time    import sleep

def energiza(V1, V2, V3):
    L1.value(V1)
    L2.value(V2)
    L3.value(V3)
    sleep(1)

L1= Pin(18, Pin.OUT)
L2= Pin(19, Pin.OUT)
L3= Pin(21, Pin.OUT)

while(1):
    energiza(1, 0, 1)
    energiza(0, 1, 0)
    energiza(1, 1, 0)