Messing with NeoPixels in Micropython

neopixels.py

from machine import Pin
from neopixel import NeoPixel
import time

pixels = NeoPixel(Pin(0), 12, bpp=4)

WHITE = (0,0,0,255)
RED = (255,0,0,0)
GREEN = (0,255,0,0)
BLUE = (0,0,255,0)
BLACK = (0,0,0,0)

def colorwheel(pos):
    if pos < 0 or pos > 255:  return (0, 0, 0)
    if pos < 85: return (255 - pos * 3, pos * 3, 0)
    if pos < 170: pos -= 85; return (0, 255 - pos * 3, pos * 3)
    pos -= 170; return (pos * 3, 0, 255 - pos * 3)

def set_brightness(color, brightness=1):
    return tuple(int(c * brightness) for c in color)

def set_pixel(pixel, color, brightness=1):
    pixels[pixel] = set_brightness(color, brightness)
    pixels.write()

def set_all_pixels(color, brightness=1):
    pixels.fill(set_brightness(color, brightness))
    pixels.write()
    
# for color in (WHITE, RED, GREEN, BLUE, BLACK):
#     set_all_pixels(color, .25)
#     time.sleep(1)
#

CLOCKWISE = -1
COUNTER_CLOCKWISE = 1

def animate(pattern, speed=0.1, rotation=COUNTER_CLOCKWISE):
    if rotation == None:
        rotation = COUNTER_CLOCKWISE
    print(pattern)
    while True:
        for p in range(0,12):
            set_pixel(p, pattern[p], 0.2)
        pattern = pattern[rotation:] + pattern[:rotation]
        time.sleep(speed)        

def show_rainbow(speed=0.025, rotation=None):
    rainbow = [(colorwheel(c * 21) + (0,)) for c in range(12)]
    animate(rainbow, speed, rotation)

def show_comet(speed=0.025, rotation=None, length=6):
    if length < 3:
        length = 3
    if length > 12:
        length = 12
    comet = [(0, 0, 0, b * 4) for b in reversed(range(length))] + [(0, 0, 0, 0) for _ in range(12 - length)]
    animate(comet, speed, rotation)
    
def marching_ants(speed=0.25, rotation=None, color=BLUE):
    faded = set_brightness(color, 0.25)
    ants = [BLACK, BLACK, faded] * 6
    animate(ants, speed, rotation)
    
def chase(speed=0.25, rotation=None, color=BLUE):
    chasers = ([color] * 3 + [BLACK] * 3) * 2
    animate(chasers, speed, rotation)
    
# show_comet(0.05, rotation=CLOCKWISE, length=5)

# marching_ants(rotation=COUNTER_CLOCKWISE)

chase(speed=0.1, color=set_brightness(colorwheel(33) + (0,), 0.25))
# set_all_pixels(BLACK)