Bouncing Ball - Pygame

import pygame
import sys

W, H = 200, 500
JUMP_HEIGHT = 300
STEPS = 60
G = 2.0 * JUMP_HEIGHT / (STEPS * (STEPS - 1))
V = -(G * (STEPS - 1))

r = 25
y = H - r
x = W / 2
v = V

pygame.init()
DS = pygame.display.set_mode((W, H))
clock = pygame.time.Clock()

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT or (event.type == pygame.KEYDOWN and event.key == pygame.K_ESCAPE):
            pygame.quit()
            sys.exit()

    pygame.draw.circle(DS, (255, 255, 255), (x, int(y)), r, 0)
    pygame.display.update()
    clock.tick(60)
    DS.fill((0, 0, 0))

    y += v
    v += G
    if y > H - r:
        v = V
        y = H - r