user: Python code for a rotating square

assistant: Here's an example of Python code that generates a rotating square using the Pygame library:

```python
import pygame
import math

# Initialize Pygame
pygame.init()

# Set up the display window
size = (400, 400)
screen = pygame.display.set_mode(size)
pygame.display.set_caption("Rotating Square")

# Define some colors
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)

# Define the square's position and size
square_size = 100
square_center = (size[0] // 2, size[1] // 2)

# Set the initial rotation angle
angle = 0

# Start the game loop
running = True
while running:
    # Handle events
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
    
    # Clear the screen
    screen.fill(WHITE)
    
    # Calculate the coordinates of the four corners of the square
    corner1 = (square_center[0] - square_size // 2, square_center[1] - square_size // 2)
    corner2 = (square_center[0] + square_size // 2, square_center[1] - square_size // 2)
    corner3 = (square_center[0] + square_size // 2, square_center[1] + square_size // 2)
    corner4 = (square_center[0] - square_size // 2, square_center[1] + square_size // 2)
    
    # Rotate the corners using a rotation matrix
    sin_angle = math.sin(angle)
    cos_angle = math.cos(angle)
    rotated_corner1 = ((corner1[0] - square_center[0]) * cos_angle - (corner1[1] - square_center[1]) * sin_angle + square_center[0],
                       (corner1[0] - square_center[0]) * sin_angle + (corner1[1] - square_center[1]) * cos_angle + square_center[1])
    rotated_corner2 = ((corner2[0] - square_center[0]) * cos_angle - (corner2[1] - square_center[1]) * sin_angle + square_center[0],
                       (corner2[0] - square_center[0]) * sin_angle + (corner2[1] - square_center[1]) * cos_angle + square_center[1])
    rotated_corner3 = ((corner3[0] - square_center[0]) * cos_angle - (corner3[1] - square_center[1]) * sin_angle + square_center[0],
                       (corner3[0] - square_center[0]) * sin_angle + (corner3[1] - square_center[1]) * cos_angle + square_center[1])
    rotated_corner4 = ((corner4[0] - square_center[0]) * cos_angle - (corner4[1] - square_center[1]) * sin_angle + square_center[0],
                       (corner4[0] - square_center[0]) * sin_angle + (corner4[1] - square_center[1]) * cos_angle + square_center[1])
    
    # Draw the rotated square
    pygame.draw.polygon(screen, BLACK, [rotated_corner1, rotated_corner2, rotated_corner3, rotated_corner4])
    
    # Update the rotation angle
    angle += 0.01
    
    # Update the display
    pygame.display.flip()

# Clean up
pygame.quit()
```

This code uses the Pygame library to create a window and draw a rotating square on it. The position and size of the square are defined, and the square is rotated using a rotation matrix. The rotation angle is updated each frame to make the square appear to rotate. The pygame.draw.polygon() function is used to draw the rotated square on the screen.

To run this code, you will need to have Pygame installed on your system. You can install Pygame using pip:

```
pip install pygame
```

Once Pygame is installed, you can run the code by saving it to a file (e.g. `rotating_square.py`) and running the following command in your terminal:

```
python rotating_square.py
```

This should open a window showing a rotating square. You can close the window by clicking the close button or pressing the `Esc` key.