import machine
import time
import neopixel

pin = machine.Pin(13)
np = neopixel.NeoPixel(pin,16)

def set_color(r, g, b):
    for i in range (16):
        np[i] = (r, g, b)
        np.write()

while True:
    set_color(255, 0, 0)
    time.sleep(1)
    set_color(0, 255, 0)
    time.sleep(1)
    set_color(0, 0, 255)
    time.sleep(1)
    set_color(255, 255, 0)
    time.sleep(1)