# ~ shihao zhao--LED lab
import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
import time 

pins=[17,18,27,22]

for i,pin in enumerate(pins):
	GPIO.setup(pin,GPIO.OUT)
	for j in range(i+1):
		GPIO.output(pin,0)
		time.sleep(0.5)
		GPIO.output(pin,1)
		time.sleep(0.5)
GPIO.cleanup()
