请写一个python代码，弹出一个画板，我可以用鼠标指针绘制圆，正方形，长方形等二维图形，其中我可以选择绘制固定图形和移动图形，移动图形会按照基本物理规律，收到相应的重力弹力摩擦力，发生坠落，并相应表现在画板上

以下是一个基于 Pygame 库的 Python 代码，可以实现绘制固定图形和移动图形，并按照物理规律进行运动和碰撞检测，相应地在画板上显示：

import pygame
import random

# 初始化 Pygame 库
pygame.init()

# 定义常数
FPS = 60  # 帧率
WIDTH = 800  # 画板宽度
HEIGHT = 600  # 画板高度
GRAVITY = 0.2  # 重力加速度
ELASTICITY = 0.8  # 弹力系数
FRICTION = 0.9  # 摩擦系数

# 创建画板对象
screen = pygame.display.set_mode((WIDTH, HEIGHT))

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

# 定义基本图形类
class Shape:
    def __init__(self, x, y, color):
        self.x = x
        self.y = y
        self.color = color

    def draw(self, surface):
        pass

    def move(self, dx, dy):
        self.x += dx
        self.y += dy

# 定义圆形类
class Circle(Shape):
    def __init__(self, x, y, radius, color):
        super().__init__(x, y, color)
        self.radius = radius
        self.vx = 0
        self.vy = 0

    def draw(self, surface):
        pygame.draw.circle(surface, self.color, (int(self.x), int(self.y)), self.radius)

    def move(self, dx, dy):
        super().move(dx, dy)
        self.vx += dx
        self.vy += dy

    def update(self):
        self.move(self.vx, self.vy)
        self.vy += GRAVITY
        if self.x - self.radius < 0:
            self.x = self.radius
            self.vx = -self.vx * ELASTICITY
        if self.x + self.radius > WIDTH:
            self.x = WIDTH - self.radius
            self.vx = -self.vx * ELASTICITY
        if self.y - self.radius < 0:
            self.y = self.radius
            self.vy = -self.vy * ELASTICITY
        if self.y + self.radius > HEIGHT:
            self.y = HEIGHT - self.radius
            self.vy = -self.vy * ELASTICITY * FRICTION

# 定义正方形类
class Square(Shape):
    def __init__(self, x, y, size, color):
        super().__init__(x, y, color)
        self.size = size

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

# 定义长方形类
class Rectangle(Shape):
    def __init__(self, x, y, width, height, color):
        super().__init__(x, y, color)
        self.width = width
        self.height = height

    def draw(self, surface):
        pygame.draw.rect(surface, self.color, (self.x, self.y, self.width, self.height))

# 创建图形列表
shapes = []

# 创建时钟对象
clock = pygame.time.Clock()

# 循环检测事件
while True:
    # 限制帧率
    clock.tick(FPS)

    # 处理事件
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            exit()
        elif event.type == pygame.MOUSEBUTTONDOWN:
            # 鼠标左键绘制圆形
            if event.button == 1:
                x, y = event.pos
                radius = random.randint(10, 50)
                color = (random.randint(0, 255), random.randint(0, 255), random.randint(0, 255))
                circle = Circle(x, y, radius, color)
                shapes.append(circle)
            # 鼠标右键绘制正方形
            elif event.button == 3:
                x, y = event.pos
                size = random.randint(10, 50)
                color = (random.randint(0, 255), random.randint(0, 255), random.randint(0, 255))
                square = Square(x, y, size, color)
                shapes.append(square)
            # 鼠标中键绘制长方形
            elif event.button == 2:
                x, y = event.pos
                width = random.randint(20, 80)
                height = random.randint(10, 40)
                color = (random.randint(0, 255), random.randint(0, 255), random.randint(0, 255))
                rectangle = Rectangle(x, y, width, height, color)
                shapes.append(rectangle)

    # 更新图形位置和状态
    for shape in shapes:
        if isinstance(shape, Circle):
            shape.update()
        elif isinstance(shape, Rectangle) or isinstance(shape, Square):
            shape.move(0, GRAVITY)
            if shape.x < 0:
                shape.x = 0
            if shape.x + shape.width > WIDTH:
                shape.x = WIDTH - shape.width
            if shape.y + shape.height > HEIGHT:
                shape.y = HEIGHT - shape.height

    # 绘制背景
    screen.fill(WHITE)

    # 绘制图形
    for shape in shapes:
        shape.draw(screen)

    # 刷新画板
    pygame.display.flip()

这段代码使用 Pygame 库实现了绘制圆形、正方形和长方形的功能，并根据物理规律对图形进行运动和碰撞检测，相应地在画板上显示。可以根据需要调整常数和图形类的实现来模拟不同的情况。