import pygame
import random
import sys


size = width, height = (700,500)
values = [None] * width
i = 0
j = 0

def setup():
    global win

    pygame.init()
    win = pygame.display.set_mode(size)

    for i in range(len(values)):
        values[i] = i + 1
    random.shuffle(values)

def events():
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

def draw():
    global i, j

    win.fill((0,0,0))

    a = values[j]
    b = values[j + 1]
    if a > b:
        swap(values, j, j + 1)

    if i < len(values):
        j += 1
        if j == (len(values) - i - 1):
            j = 0
            i += 1

    for i in range(len(values)):
        pygame.draw.line(win, (255,255,255), (i, height), (i, height - values[i]), 1)

    pygame.display.update()

def swap(arr, a, b):
    temp = arr[a]
    arr[a] = arr[b]
    arr[b] = temp


setup()
while True:
    events()
    draw()