import pygame
import sys
from pygame.locals import *

class Snake:
    def __init__(self, start_position, length=3):
        self.body = [start_position] * length
        self.direction = (0, 1)  # Initially, the snake is moving to the right

    def move(self):
        head_x, head_y = self.body[0]
        dir_x, dir_y = self.direction
        new_head = (head_x + dir_x, head_y + dir_y)
        self.body.insert(0, new_head)
        self.body.pop()

    def change_direction(self, new_direction):
        if (new_direction[0] == -self.direction[0] and new_direction[1] == -self.direction[1]):
            return
        self.direction = new_direction

    def grow(self):
        self.body.append(self.body[-1])

# Initialize Pygame
pygame.init()
window_size = (400, 400)
screen = pygame.display.set_mode(window_size)
clock = pygame.time.Clock()

# Create a snake at position (20, 20)
snake = Snake((20, 20))

# Main game loop
while True:
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()
        elif event.type == KEYDOWN:
            if event.key == K_UP:
                snake.change_direction((0, -1))
            elif event.key == K_DOWN:
                snake.change_direction((0, 1))
            elif event.key == K_LEFT:
                snake.change_direction((-1, 0))
            elif event.key == K_RIGHT:
                snake.change_direction((1, 0))

    # Move the snake
    snake.move()

    # Clear screen
    screen.fill((0, 0, 0))
    # Draw the snake (for simplicity, we will just print its position)
    for part in snake.body:
        print(part)  # In a real game, you would draw the snake on the screen here

    # Update display
    pygame.display.update()
    clock.tick(10)  # Limit the frame rate to 10 FPS