Código de Python - Juego de la serpiente con PyGame

#Snake Tutorial Python

import math

import random

import pygame

import tkinter as tk

from tkinter import messagebox

class cube(object):

    rows = 20

    w = 500

    def __init__(self,start,dirnx=1,dirny=0,color=(255,0,0)):

        self.pos = start

        self.dirnx = 1

        self.dirny = 0

        self.color = color

    def move(self, dirnx, dirny):

        self.dirnx = dirnx

        self.dirny = dirny

        self.pos = (self.pos[0] + self.dirnx, self.pos[1] + self.dirny)

    def draw(self, surface, eyes=False):

        dis = self.w // self.rows

        i = self.pos[0]

        j = self.pos[1]

        pygame.draw.rect(surface, self.color, (i*dis+1,j*dis+1, dis-2, dis-2))

        if eyes:

            centre = dis//2

            radius = 3

            circleMiddle = (i*dis+centre-radius,j*dis+8)

            circleMiddle2 = (i*dis + dis -radius*2, j*dis+8)

            pygame.draw.circle(surface, (0,0,0), circleMiddle, radius)

            pygame.draw.circle(surface, (0,0,0), circleMiddle2, radius)

class snake(object):

    body = []

    turns = {}

    def __init__(self, color, pos):

        self.color = color

        self.head = cube(pos)

        self.body.append(self.head)

        self.dirnx = 0

        self.dirny = 1

    def move(self):

        for event in pygame.event.get():

            if event.type == pygame.QUIT:

                pygame.quit()

            keys = pygame.key.get_pressed()

            for key in keys:

                if keys[pygame.K_LEFT]:

                    self.dirnx = -1

                    self.dirny = 0

                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]

                elif keys[pygame.K_RIGHT]:

                    self.dirnx = 1

                    self.dirny = 0

                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]

                elif keys[pygame.K_UP]:

                    self.dirnx = 0

                    self.dirny = -1

                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]

                elif keys[pygame.K_DOWN]:

                    self.dirnx = 0

                    self.dirny = 1

                    self.turns[self.head.pos[:]] = [self.dirnx, self.dirny]

        for i, c in enumerate(self.body):

            p = c.pos[:]

            if p in self.turns:

                turn = self.turns[p]

                c.move(turn[0],turn[1])

                if i == len(self.body)-1:

                    self.turns.pop(p)

            else:

                if c.dirnx == -1 and c.pos[0] <= 0: c.pos = (c.rows-1, c.pos[1])

                elif c.dirnx == 1 and c.pos[0] >= c.rows-1: c.pos = (0,c.pos[1])

                elif c.dirny == 1 and c.pos[1] >= c.rows-1: c.pos = (c.pos[0], 0)

                elif c.dirny == -1 and c.pos[1] <= 0: c.pos = (c.pos[0],c.rows-1)

                else: c.move(c.dirnx,c.dirny)

    def reset(self, pos):

        self.head = cube(pos)

        self.body = []

        self.body.append(self.head)

        self.turns = {}

        self.dirnx = 0

        self.dirny = 1

    def addCube(self):

        tail = self.body[-1]

        dx, dy = tail.dirnx, tail.dirny

        if dx == 1 and dy == 0:

            self.body.append(cube((tail.pos[0]-1,tail.pos[1])))

        elif dx == -1 and dy == 0:

            self.body.append(cube((tail.pos[0]+1,tail.pos[1])))

        elif dx == 0 and dy == 1:

            self.body.append(cube((tail.pos[0],tail.pos[1]-1)))

        elif dx == 0 and dy == -1:

            self.body.append(cube((tail.pos[0],tail.pos[1]+1)))

        self.body[-1].dirnx = dx

        self.body[-1].dirny = dy

    def draw(self, surface):

        for i, c in enumerate(self.body):

            if i ==0:

                c.draw(surface, True)

            else:

                c.draw(surface)

def drawGrid(w, rows, surface):

    sizeBtwn = w // rows

    x = 0

    y = 0

    for l in range(rows):

        x = x + sizeBtwn

        y = y + sizeBtwn

        pygame.draw.line(surface, (255,255,255), (x,0),(x,w))

        pygame.draw.line(surface, (255,255,255), (0,y),(w,y))

def redrawWindow(surface):

    global rows, width, s, snack

    surface.fill((0,0,0))

    s.draw(surface)

    snack.draw(surface)

    drawGrid(width,rows, surface)

    pygame.display.update()

def randomSnack(rows, item):

    positions = item.body

    while True:

        x = random.randrange(rows)

        y = random.randrange(rows)

        if len(list(filter(lambda z:z.pos == (x,y), positions))) > 0:

            continue

        else:

            break

    return (x,y)

def message_box(subject, content):

    root = tk.Tk()

    root.attributes("-topmost", True)

    root.withdraw()

    messagebox.showinfo(subject, content)

    try:

        root.destroy()

    except:

        pass

def main():

    global width, rows, s, snack

    width = 500

    rows = 20

    win = pygame.display.set_mode((width, width))

    s = snake((255,0,0), (10,10))

    snack = cube(randomSnack(rows, s), color=(0,255,0))

    flag = True

    clock = pygame.time.Clock()

    while flag:

        pygame.time.delay(50)

        clock.tick(10)

        s.move()

        if s.body[0].pos == snack.pos:

            s.addCube()

            snack = cube(randomSnack(rows, s), color=(0,255,0))

        for x in range(len(s.body)):

            if s.body[x].pos in list(map(lambda z:z.pos,s.body[x+1:])):

                print('Score: ', len(s.body))

                message_box('You Lost!', 'Play again...')

                s.reset((10,10))

                break

        redrawWindow(win)

    pass

main()