pygame demo

pygame_demo.py

import pygame as pg
pg.init()

width = 500
height = 500
screen = pg.display.set_mode((width, height))

# (x, y) coordinates. We'll put it right in the middle.
x = width / 2
y = height / 2

for radius in range(100, 0, -1):
    red = 255
    green = radius * 2  # just to make the color change
    blue = 0
    pg.draw.circle(screen, (red, green, blue), (x, y), radius)

# this makes the screen actually update:
pg.display.flip()