from time import sleep
import RPi.GPIO as GPIO

GPIO.setmode(GPIO.BCM)
GPIO.setup(20, GPIO.OUT)
GPIO.setup(21, GPIO.OUT)

GPIO.output(21, GPIO.HIGH)
for x in range(200):
	GPIO.output(20, GPIO.HIGH)
	sleep(0.005)
	GPIO.output(20, GPIO.LOW)
	sleep(0.005)

sleep(0.5)

GPIO.output(21, GPIO.LOW)
for x in range(200):
	GPIO.output(20, GPIO.HIGH)
	sleep(0.005)
	GPIO.output(20, GPIO.LOW)
	sleep(0.005)