Pygame

                           GPL License

                           SDL

Simple DirectMedia Layer         
 development library which   
 provide low level access to 
  audio, keyboard, mouse,  
  joystick, and graphics hardware 
          via 
  OpenGL and Direct3D.

import pygame, sys
from pygame.locals import *

pygame.init()
DISPLAYSURF = pygame.display.set_mode((400, 300))
pygame.display.set_caption('Hello World!')while True: # main game loop
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()
    pygame.display.update()

Game itself

- board

- Snake

- WASD

                        - Collision detection

import random, pygame, sys
from pygame.locals import *

FPS = 15
WINDOWWIDTH = 640
WINDOWHEIGHT = 480
CELLSIZE = 20
assert WINDOWWIDTH % CELLSIZE == 0,
assert WINDOWHEIGHT % CELLSIZE == 0,

CELLWIDTH =  int(WINDOWWIDTH / CELLSIZE)
CELLHEIGHT = int(WINDOWHEIGHT / CELLSIZE)

WHITE     = (255,255,255)
BLACK     = (0,0,0)RED       = (255,0,0)
GREEN     = (0,255,0)
DARKGREEN = (0,155,0)
DARKGRAY  = (40,40,40)
BGCOLOR = BLACK

UP = 'up'
DOWN = 'down'
LEFT = 'left'
RIGHT = 'right'
HEAD = 0

def main():
    global FPSCLOCK, DISPLAYSURF, BASICFONT

    pygame.init()
    FPSCLOCK = pygame.time.Clock()
    DISPLAYSURF = pygame.display.set_mode((WINDOWWIDTH, WINDOWHEIGHT))
    BASICFONT = pygame.font.Font('freesansbold.ttf', 18)
    pygame.display.set_caption('Snake')
    
    showStartScreen()
    while True:
        runGame()
        showGameOverScreen() 

def runGame():
    
    startx = random.randint(5, CELLWIDTH - 6) 
    starty = random.randint(5, CELLHEIGHT - 6)

    wormCoords = [{'x': startx,'y': starty}, 
                  {'x': startx - 1, 'y': starty},
                  {'x': startx - 2, 'y': starty}]
    direction = RIGHT

    apple = getRandomLocation() 

while True: 
    for event in pygame.event.get():
        if event.type == QUIT:
            terminate()
        elif event.type == KEYDOWN:
            if (event.key == K_LEFT or event.key == K_a) and direction
!= RIGHT: 

             direction = LEFT        elif (event.key == K_RIGHT or event.key == K_d) and
direction != LEFT:

             direction = RIGHT
        elif (event.key == K_UP or event.key == K_w) and
direction != DOWN             direction = UP:        elif (event.key == K_DOWN or event.key == K_s) and
direction != UP                 direction = DOWN

         elif event.key == K_ESCAPE:
             terminate() 

if wormCoords[HEAD]['x'] == -1 or wormCoords[HEAD]['x'] ==
CELLWIDTH or wormCoords[HEAD]['y'] == -1 or wormCoords[HEAD]['y'] ==
CELLHEIGHT:
    return # game over

for wormBody in wormCoords[1:]:
    if wormBody['x'] == wormCoords[HEAD]['x'] and wormBody['y'] ==
wormCoords[HEAD]['y']:
        return # game over 

if direction == UP:
    newHead = {'x': wormCoords[HEAD]['x'], 'y':wormCoords[HEAD]['y'] - 1}
elif direction == DOWN:
    newHead = {'x': wormCoords[HEAD]['x'], 'y':wormCoords[HEAD]['y'] + 1}
elif direction == LEFT:
    newHead = {'x': wormCoords[HEAD]['x'] - 1, 'y':wormCoords[HEAD]['y']}
elif direction == RIGHT:
    newHead = {'x': wormCoords[HEAD]['x'] + 1, 'y':wormCoords[HEAD]['y']}
wormCoords.insert(0, newHead)
 

DISPLAYSURF.fill(BGCOLOR)
drawGrid()
drawWorm(wormCoords)
drawApple(apple)
drawScore(len(wormCoords) - 3)
pygame.display.update()
FPSCLOCK.tick(FPS) 

def showGameOverScreen():
    gameOverFont = pygame.font.Font('freesansbold.ttf', 150)
    gameSurf = gameOverFont.render('Game', True, WHITE)
    overSurf = gameOverFont.render('Over', True, WHITE)
    gameRect = gameSurf.get_rect()
    overRect = overSurf.get_rect()
    gameRect.midtop = (WINDOWWIDTH / 2, 10)

    overRect.midtop = (WINDOWWIDTH / 2, gameRect.height + 10 + 25)

    DISPLAYSURF.blit(gameSurf, gameRect)
    DISPLAYSURF.blit(overSurf, overRect)
    drawPressKeyMsg()
    pygame.display.update()

    pygame.time.wait(500)
    checkForKeyPress() # clear out any key presses in the event queue
    while True:
        if checkForKeyPress():
            pygame.event.get() # clear event queue
            return