import pygame
import random

WIDTH = 500
HEIGHT = 500
FPS = 5

WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)

pygame.init()
screen = pygame.display.set_mode((WIDTH, HEIGHT))
clock = pygame.time.Clock()

speedY = 0
speedX = random.randint(0,19)*25
running = True
state = []
for index in range(0,400,1):
 state.append(1)
for index in range(0,20,1):
 state[19*index +(index-1) + 20] = 2

index_X = []
for index in range(0,20,1):
 index_X.append(20)
 
flag_down = 1
 
while running:
    
    clock.tick(FPS)
    
    for event in pygame.event.get():
        if (speedY < 0): speedY = 0
        if (speedY > 475):speedY = 475
        
        if event.type == pygame.QUIT:
            running = False
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT and speedX > 0:
                speedX -= 25
            if event.key == pygame.K_RIGHT and speedX < 475:
                speedX += 25
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT and speedX > 0:
                speedX -= 25
            if event.key == pygame.K_RIGHT and speedX < 475:
                speedX += 25
                
    
    screen.fill(BLACK)
    counter = 0
    for it_1 in range(0,500,25):
     for it_2 in range(0,500,25):
      if (state[counter]==1):
         pygame.draw.rect(screen,WHITE, (it_1,it_2,24,24))
      if (state[counter]==2):
              
         pygame.draw.rect(screen,RED, (it_1,it_2,24,24))
      
      counter = counter + 1 
       
    pygame.draw.rect(screen,RED, (speedX,speedY,24,24))
    pygame.display.flip()
    speedY = speedY + 25
 
    if speedY > 475:
     x = speedX//25
     print(index_X[x])
     if (state[19*x +(x-1) + index_X[x]] == 2):
      index_X[x] -= 1
      state[19*x +(x-1) + index_X[x]] = 2
     speedY = 0
     speedX = random.randint(0,19)*25
pygame.quit()