Classic snake game, built with the Turtle( ) module, inside the library of "turtle" in Python.

food.py

from turtle import Turtle
import random
class Food(Turtle):

    def __init__(self):
        super().__init__()
        self.refresh()
        self.shape("circle")
        self.penup()
        self.shapesize(stretch_len=0.5, stretch_wid=0.5)
        self.color("blue")
        self.speed("fastest")


    def refresh(self):
        random_x=random.randint(-280,280)
        random_y=random.randint(-280,280)
        self.goto(random_x,random_y)

main.py

from turtle import Screen
from snake import Snake
from food import Food
from scoreboard import Scoreboard
import time

screen = Screen()
screen.setup(width=600, height=600)
screen.bgcolor("black")
screen.title("My Snake Game")
screen.tracer(0)

snake = Snake()
food = Food()
scoreboard = Scoreboard()

screen.listen()
screen.onkey(snake.up, "Up")
screen.onkey(snake.down, "Down")
screen.onkey(snake.right, "Right")
screen.onkey(snake.left, "Left")

game_is_on = True
while game_is_on:
    screen.update()
    time.sleep(0.1)
    snake.move()

    # Detect collision with food.
    if snake.head.distance(food) < 15:
        food.refresh()
        snake.extend()
        scoreboard.increase_score()

    # Detect collision with the wall.
    if snake.head.xcor() > 280 or snake.head.xcor() < -280 or snake.head.ycor() > 280 or snake.head.ycor() < -280:
        game_is_on = False
        scoreboard.game_over()

    # Detect collision with tail.
    for segment in snake.segments[1:]:
        if snake.head.d istance < 10:
            game_is_on = False
            scoreboard.game_over()
    # if head collides with any segment in the tail:
    # trigger game_over

screen.exitonclick()

scoreboard.py

from turtle import Turtle
ALIGNMENT="center"
FONT=("Courier",24,"normal")
class Scoreboard(Turtle):
    def __init__(self):
        super().__init__()
        self.score = 0
        self.color("white")
        self.hideturtle()
        self.penup()
        self.goto(0,260)
        self.update_scoreboard()

    def update_scoreboard(self):
        self.write(f"Score: {self.score}", align="center", font=("Arial", 24, "normal"))

    def increase_score(self):
        self.score += 1
        self.clear()
        self.update_scoreboard()

    def game_over(self):
        self.goto(0,0)
        self.write("GAME OVER", align=ALIGNMENT,font=FONT)

snake.py

from turtle import Turtle
import time

STARTING_POSITIONS = [(0, 0), (-20, 0), (-40, 0)]
MOVE_DISTANCE = 20
UP = 90
DOWN = 270
RIGHT = 0
LEFT = 180


class Snake(Turtle):
    def __init__(self):
        super().__init__()
        self.segments = []
        self.create_snake()
        self.head = self.segments[0]

    def create_snake(self):
        for position in STARTING_POSITIONS:
            self.add_segment(position)

    def move(self):
        for seg_num in range(len(self.segments) - 1, 0, -1):
            new_x = self.segments[seg_num - 1].xcor()
            new_y = self.segments[seg_num - 1].ycor()
            self.segments[seg_num].goto(new_x, new_y)
        self.head.forward(20)

    def add_segment(self,position):
        new_segment = Turtle("square")
        new_segment.color("white")
        new_segment.penup()
        new_segment.goto(position)
        self.segments.append(new_segment)

    def extend(self):
        self.add_segment(self.segments[-1].position())



    def up(self):
        if self.head.heading() != DOWN:
            self.head.setheading(UP)

    def down(self):
        if self.head.heading() != UP:
            self.head.setheading(DOWN)

    def right(self):
        if self.head.heading() != LEFT:
            self.head.setheading(RIGHT)

    def left(self):
        if self.head.heading() != RIGHT:
            self.head.setheading(LEFT)