Create a animation of a katana swinging

Here's a simple example of how you can create an animation of a katana swinging using the Pygame library in Python.

```python
import pygame
import math

# Window size
WIDTH, HEIGHT = 800, 600

# Colors
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
RED = (255, 0, 0)

class Katana:
    def __init__(self):
        self.x = WIDTH // 2
        self.y = HEIGHT // 2
        self.length = 100
        self.angle = 0
        self.speed = 0.05

    def draw(self, screen):
        # Draw the katana
        end_x = self.x + math.cos(self.angle) * self.length
        end_y = self.y + math.sin(self.angle) * self.length
        pygame.draw.line(screen, RED, (self.x, self.y), (end_x, end_y), 5)

    def update(self):
        # Update the angle
        self.angle += self.speed

def main():
    pygame.init()
    screen = pygame.display.set_mode((WIDTH, HEIGHT))
    clock = pygame.time.Clock()

    katana = Katana()

    running = True
    while running:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                running = False

        screen.fill(BLACK)
        katana.draw(screen)
        katana.update()

        # Draw the katana's hilt
        pygame.draw.rect(screen, WHITE, (katana.x - 20, katana.y - 20, 40, 40))

        pygame.display.flip()
        clock.tick(60)

    pygame.quit()

if __name__ == "__main__":
    main()
```

This script will create a window with a black background and a red katana swinging back and forth. The katana's hilt is represented by a white rectangle.

Please note that you need to have the Pygame library installed to run this script. You can install it using pip:

```bash
pip install pygame
```