from machine import Pin
import time
red=Pin(0,Pin.OUT)
green=Pin(1,Pin.OUT)
blue=Pin(2,Pin.OUT)
while True:
    red.on()
    time.sleep(0.5)
    red.off()
    green.on()
    time.sleep(0.5)
    green.off()
    blue.on()
    time.sleep(0.5)
    blue.off()