from machine import Pin
from time import sleep
red=Pin(19,Pin.OUT)
green=Pin(18,Pin.OUT)
blue=Pin(16,Pin.OUT)
while True:
    red.on()
    sleep(.5)
    red.off()
    sleep(.5)
    green.on()
    sleep(.5)
    green.off()
    sleep(.5)
    blue.on()
    sleep(.5)
    blue.off()
    sleep(.5)