# A simple worm game, 2nd attempt.

    import pygame, random

    class Worm:
        def __init__(self, surface):
            self.surface = surface
            self.x = surface.get_width() / 2
            self.y = surface.get_height() / 2
            self.length = 1
            self.grow_to = 50
            self.vx = 0
            self.vy = -1
            self.body = []
            self.crashed = False
            self.color = 255, 255, 0

        def eat(self):
            self.grow_to += 25

        def event(self, event):
            """ Handle keyboard events. """
            if event.key == pygame.K_UP:
                if self.vy == 1: return
                self.vx = 0
                self.vy = -1
            elif event.key == pygame.K_DOWN:
                if self.vy == -1: return
                self.vx = 0
                self.vy = 1
            elif event.key == pygame.K_LEFT:
                if self.vx == 1: return
                self.vx = -1
                self.vy = 0
            elif event.key == pygame.K_RIGHT:
                if self.vx == -1: return
                self.vx = 1
                self.vy = 0

        def move(self):
            """ Move the worm. """
            self.x += self.vx
            self.y += self.vy

            if (self.x, self.y) in self.body:
                self.crashed = True
            self.body.insert(0, (self.x, self.y))
            if (self.grow_to > self.length):
                self.length += 1

            if len(self.body) > self.length:
                self.body.pop()

        def draw(self):
            #for x, y in self.body:
            #    self.surface.set_at((x, y), self.color)
            x, y = self.body[0]
            self.surface.set_at((int(x), int(y)), self.color)
            x, y = self.body[-1]
            self.surface.set_at((int(x), int(y)), (0, 0, 0))

    class Food:
        def __init__(self, surface):
            self.surface = surface
            self.x = random.randint(0, surface.get_width())
            self.y = random.randint(0, surface.get_height())
            self.color = 255, 255, 255

        def draw(self):
            pygame.draw.rect(self.surface, self.color, (self.x, self.y, 3, 3), 0)

        def erase(self):
            pygame.draw.rect(self.surface, (0, 0, 0), (self.x, self.y, 3, 3), 0)

        def check(self, x, y):
            if x < self.x or x > self.x + 3:
                return False
            elif y < self.y or y > self.y + 3:
                return False
            else:
                return True

    w = 500
    h = 500

    screen = pygame.display.set_mode((w, h))
    clock = pygame.time.Clock()
    pygame.mixer.init()
    chomp = pygame.mixer.Sound("chomp.wav")

    score = 0
    worm = Worm(screen)
    food = Food(screen)
    running = True

    while running:
        #screen.fill((0, 0, 0))
        worm.move()
        worm.draw()
        food.draw()
        if worm.crashed:
            running = False
        elif worm.x <= 0 or worm.x >= w - 1:
            running = False
        elif worm.y <= 0 or worm.y >= h - 1:
            running = False
        elif food.check(worm.x, worm.y):
            score += 1
            worm.eat()
            chomp.play()
            print ( "Score: %d" % score)
            food.erase()
            food = Food(screen)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                running = False
            elif event.type == pygame.KEYDOWN:
                worm.event(event)
        pygame.display.flip()
        clock.tick(60)