import neopixel
from machine import Pin
from time import sleep

NUM_LED = 24

leds = neopixel.NeoPixel(Pin(15), NUM_LED)

while True:
    for i in range(NUM_LED):
        if i % 2 == 0:
            leds[i] = (200, 0, 0)  
        else:
            leds[i] = (0, 0, 200)  
    leds.write()
    sleep(1)
    for i in range(NUM_LED):
        if i % 2 == 1:
            leds[i] = (200, 0, 0)  
        else:
            leds[i] = (0, 0, 200)  
    leds.write()
    sleep(1)