# Reference: https://wokwi.com/projects/392212703822168065
# Reference: https://wokwi.com/projects/392220419950952449

from machine import Pin
import time
import neopixel

ws_pin = 13
NUMPIXELS = 256

# Initialize NeoPixel strip
pixels = neopixel.NeoPixel(Pin(ws_pin), NUMPIXELS)

def display_reducing_square():
  for size in range(16, 1, -8):
    rainbow_square(size)
    pixels.write() # 更新 LED 顯示
    time.sleep(1)

def rainbow_square(size):
  for i in range(size):
    color = wheel((i * 256 // size) & 255)
    # Fill top row
    for col in range(i, size):
      pixels[i * 16 + col] = color
    # Fill bottom row
    for col in range(i, size):
      pixels[(size - 1) * 16 + col] = color
    # Fill left column
    for row in range(i + 1, size - 1):
      pixels[row * 16 + i] = color
    # Fill right column
    for row in range(i + 1, size - 1):
      pixels[row * 16 + size - 1] = color

def wheel(wheel_pos):
  wheel_pos = 255 - wheel_pos
  if wheel_pos < 85:
    return (255 - wheel_pos * 3, 0, wheel_pos * 3)
  if wheel_pos < 170:
    wheel_pos -= 85
    return (0, wheel_pos * 3, 255 - wheel_pos * 3)
  wheel_pos -= 170
  return (wheel_pos * 3, 255 - wheel_pos * 3, 0)

while True:
  display_reducing_square()