from machine import Pin
from utime import sleep

Pin1 = Pin(8, machine.Pin.OUT)
Pin2 = Pin(11, machine.Pin.OUT)
Pin3 = Pin(15, machine.Pin.OUT)

Pins = [Pin1, Pin2, Pin3]

while True:
    for Pin in Pins:
        Pin.value(1)
        time.sleep(1.4)
        Pin.value(0)