# https://bipes.net.br/pico/ui/#nmyo54
from machine import Pin
import neopixel
import time

numberOfPixels = None
k = None

def upRange(start, stop, step):
  while start <= stop:
    yield start
    start += abs(step)

def downRange(start, stop, step):
  while start >= stop:
    yield start
    start -= abs(step)


numberOfPixels = 60
np=neopixel.NeoPixel(Pin(13),numberOfPixels)
while True:
  k_end = float(numberOfPixels - 1)
  for k in (0 <= k_end) and upRange(0, k_end, 1) or downRange(0, k_end, 1):
    np[k]=(0,0,0)
  k_end2 = float(numberOfPixels - 1)
  for k in (0 <= k_end2) and upRange(0, k_end2, 1) or downRange(0, k_end2, 1):
    np[k]=(255,0,0)
    np.write()
    time.sleep_ms(50)