Xiao RP2040 pixel fade in CP

code.py

import time
import neopixel
import board
import math

import adafruit_rgbled

pixel = neopixel.NeoPixel(board.NEOPIXEL, 1)
pixel.fill((255, 0, 255))

rgb_led = adafruit_rgbled.RGBLED(board.LED_RED, board.LED_GREEN, board.LED_BLUE, invert_pwm=True)
rgb_led.color = (255, 0, 255)

DELAY = 0.02

while True:

    # sine (cosine) fade
    print("Sine")
    rgb_led.color = (255,0,255)
    pixel.fill((255, 0, 255))
    for _ in range(2):
        for i in range(100):
            rgb_led.color = tuple(
                int(x * (1 - abs(math.cos(math.pi * i / 100))) / 4)
                for x in (255,0,255)
            )
            pixel.brightness = (1 - abs(math.cos(math.pi * i / 100))) / 4
            time.sleep(DELAY)

    # square fade
    print("Square")
    rgb_led.color = (0, 255, 0)
    pixel.fill((0, 255, 0))
    for _ in range(2):
        for i in range(0,50):
            pixel.brightness = (i**2) / 100 / 100
            rgb_led.brightness = rgb_led.color = tuple(
                int(x * (i**2) / 100 / 100)
                for x in (0,255,0)
            )
            time.sleep(DELAY)
        for i in range(50,0,-1):
            pixel.brightness = (i**2) / 100 / 100
            rgb_led.brightness = rgb_led.color = tuple(
                int(x * (i**2) / 100 / 100)
                for x in (0,255,0)
            )
            time.sleep(DELAY)