import neopixel 

from machine import Pin 

from time import sleep 
import random

NUM_LED = 60

leds = neopixel.NeoPixel(Pin(5), NUM_LED) 

x=NUM_LED-1
while True:
    r=random.randint(0,259)
    g=random.randint(0,259)
    b=random.randint(0,259)
    for i in range(NUM_LED):
        if i<=x:
            leds[i]=[r, g, b]
            leds.write()
            sleep(0.05)
            leds[i]=[0,0,0]
            leds.write()    
    leds[x]=[r,g,b]
    leds.write()
    x-=1