juego snake

from turtle import *
from random import randint
from freegames import square, vector

food = vector(0, 0)
snake = [vector(10, 0)]
aim = vector(0, -10)

def change(x, y):
    "Change snake direction."
    aim.x = x
    aim.y = y

def inside(head):
    "Return True if head inside boundaries."
    return -200 < head.x < 190 and -200 < head.y < 190

def move():
    "Move snake forward one segment."
    head = snake[-1].copy()
    head.move(aim)

    if not inside(head) or head in snake:
        square(head.x, head.y, 9, 'red')
        update()
        return

    snake.append(head)

    if head == food:
        print('Snake:', len(snake))
        food.x = randint(-15, 15) * 10
        food.y = randint(-15, 15) * 10
    else: