帮我写一段俄罗斯方块的代码

好的，以下是一段简单的俄罗斯方块代码：

import pygame
import random

# 游戏区宽度
game_width = 10
game_height = 20
block_size = 30

# 定义颜色
BLACK = (0, 0, 0)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)

# 定义方块和形状
shapes = [
    [[1, 1],
     [1, 1]],

    [[0, 2, 0],
     [2, 2, 2]],

    [[0, 3, 3],
     [3, 3, 0]],

    [[4, 4, 0],
     [0, 4, 4]],

    [[5, 0, 0],
     [5, 5, 5]],

    [[0, 0, 6],
     [6, 6, 6]],

    [[7, 7, 7, 7]]
]

class Block:
    def __init__(self, x, y, shape):
        self.x = x
        self.y = y
        self.shape = shape

class Tetris:
    def __init__(self):
        self.game_over = False
        self.blocks = []
        self.init_pygame()
        self.init_blocks()

    # 初始化 Pygame
    def init_pygame(self):
        pygame.init()
        pygame.display.set_caption("俄罗斯方块")
        pygame.key.set_repeat(200, 50)
        self.screen = pygame.display.set_mode((game_width * block_size, game_height * block_size))

    # 初始化方块
    def init_blocks(self):
        self.current_block = Block(game_width // 2 - 1, 0, random.choice(shapes))
        self.next_block = Block(game_width, 0, random.choice(shapes))

    # 绘制方块
    def draw_block(self, block):
        for x in range(len(block.shape)):
            for y in range(len(block.shape[x])):
                if block.shape[x][y] != 0:
                    pygame.draw.rect(self.screen, RED, (block.x * block_size + y * block_size, block.y * block_size + x * block_size, block_size, block_size), 0)
                    pygame.draw.rect(self.screen, BLACK, (block.x * block_size + y * block_size, block.y * block_size + x * block_size, block_size, block_size), 1)

    # 绘制游戏区
    def draw(self):
        self.screen.fill(BLACK)
        for block in self.blocks:
            self.draw_block(block)
        
        self.draw_block(self.current_block)
        pygame.display.update()

    # 判断方块是否和游戏区边界相撞
    def is_collision(self, block):
        if block.x < 0 or block.x >= game_width or block.y >= game_height:
            return True
        
        for x in range(len(block.shape)):
            for y in range(len(block.shape[x])):
                if block.shape[x][y] != 0:
                    if block.y + x < 0:
                        continue
                    if self.blocks[block.y + x][block.x + y] != None:
                        return True
        return False

    # 处理方块落下
    def move_down(self):
        self.current_block.y += 1
        if self.is_collision(self.current_block):
            self.current_block.y -= 1
            self.freeze()

    # 处理方块冻结
    def freeze(self):
        for x in range(len(self.current_block.shape)):
            for y in range(len(self.current_block.shape[x])):
                if self.current_block.shape[x][y] != 0:
                    self.blocks[self.current_block.y + x][self.current_block.x + y] = self.current_block
        
        self.current_block = self.next_block
        self.current_block.x = game_width // 2 - 1
        self.current_block.y = 0
        
        if self.is_collision(self.current_block):
            self.game_over = True
        else:
            self.next_block = Block(game_width, 0, random.choice(shapes))

    # 处理方块移动
    def move(self, direction):
        x = 0
        y = 0
        if direction == pygame.K_LEFT:
            x = -1
            
        elif direction == pygame.K_RIGHT:
            x = 1
            
        elif direction == pygame.K_DOWN:
            y = 1
        
        temp_block = Block(self.current_block.x + x, self.current_block.y + y, self.current_block.shape)
        
        if not self.is_collision(temp_block):
            self.current_block.x += x
            self.current_block.y += y
            
    # 处理方块旋转
    def rotate(self):
        shape = self.current_block.shape
        shape.reverse()
        for i in range(len(shape)):
            for j in range(i):
                shape[i][j], shape[j][i] = shape[j][i], shape[i][j]

        if self.is_collision(Block(self.current_block.x, self.current_block.y, shape)):
            shape.reverse()
            for i in range(len(shape)):
                for j in range(i):
                    shape[i][j], shape[j][i] = shape[j][i], shape[i][j]
        else:
            self.current_block.shape = shape

    # 运行游戏
    def run(self):
        clock = pygame.time.Clock()
        self.blocks = [[None for _ in range(game_width)] for _ in range(game_height)]
        
        while not self.game_over:
            pygame.time.wait(100)
            for event in pygame.event.get():
                if event.type == pygame.QUIT:
                    self.game_over = True
                elif event.type == pygame.KEYDOWN:
                    if event.key == pygame.K_SPACE:
                        self.rotate()
                    else:
                        self.move(event.key)
                        
            self.move_down()
            self.draw()
            clock.tick(10)

        pygame.quit()

if __name__ == '__main__':
    tetris = Tetris()
    tetris.run()

笑话是：为什么科学家讨厌钠？因为他们觉得钠特别Na！