import time
import os
import RPi.GPIO as GPIO


GPIO.setmode(GPIO.BCM)

pins = [8,10,12,14,18,20,22,24]

for pin in pins:
   GPIO.setup(pin, GPIO.OUT) 
   GPIO.output(pin, GPIO.LOW)
   time.sleep(0.001)
   GPIO.output(pin, GPIO.HIGH)
   time.sleep(0.001)
GPIO.cleanup